The 'Campaign for East Africa', sometimes known as the 'Campaign for Abyssinia', was fought in East Africa between Allied (mainly of the British empire) and Italian forces (10 June 1940/27 November 1941).

The British Middle East Command had troops from the UK, South Africa, British India, Uganda, Kenya, Somaliland, West Africa, Northern and Southern Rhodesia, Sudan and Nyasaland, and these were supplemented by men of the Force Publique of Belgian Congo, Imperial Ethiopian Arbegnoch (Amharic for 'patriots, i. e. resistance forces) and a small Free French unit.

Italian East Africa was held by the Comando Forze Armate dell’Africa Orientale Italiana (Italian East African Armed Forces Command), with Italian units of the Regio Esercito, Regia Aeronautica and Regia Marina. The Italian forces included about 250,000 men of the Regio Corpo Truppe Coloniali (Royal Corps of Colonial Troops), led by Italian commissioned and non-commissioned officers. With the British in control of the Suez Canal, the Italian forces were cut off from supplies and reinforcement once hostilities had begun.

On 13 June 1940, there was an Italian air raid on the RAF base at Wajir in Kenya and the air war continued until the Italian forces had been pushed back from Kenya and Sudan through Somaliland, Eritrea and Ethiopia in 1940 and early in 1941. The remnants of the Italian forces in the region surrendered after the 'Battle of Gondar' in November 1941, although small groups continued to fight a guerrilla war in Ethiopia against the British until September 1943, when the Armistice of Cassibile ended the war between Italy and the Allies. The 'Campaign for East Africa' was the first Allied strategic victory in the war, and only a very small numbers of Italians escaped the region to fight in other campaigns, and the Italian defeat greatly eased the flow of supplies through the Red Sea to Egypt. Most of the Commonwealth forces were transferred to North Africa to participate in the 'Campaign for the Western Desert'.

On 9 May 1936, the Italian dictator Benito Mussolini had proclaimed the formation of Africa Orientale Italiana out of Ethiopia (recently defeated in the 2^nd Italo-Abyssinian War) and the Italian colonies of Eritrea and Somaliland. On 10 June 1940 Mussolini declared war on the UK and France, which made the substantial Italian military forces in Libya a major threat to the altogether smaller British forces in Egypt and the Italian forces of Africa Orientale Italiana a lesser danger to the British and French colonies in East Africa. Italian belligerence also closed the Mediterranean to Allied merchant shipping and endangered British sea lanes along the coast of East Africa and through the Gulf of Aden, the Red Sea and the Suez Canal. (The kingdom of Egypt remained neutral during World War II, but the terms of the Anglo-Egyptian treaty of 1936 allowed the British to occupy Egypt and the Anglo-Egyptian Sudan.) Egypt, the Suez Canal, French Somaliland and British Somaliland were also vulnerable to invasion from June 1940, but the Italian general staff had planned for war after 1942, and as a result in the summer of 1940 Italy was far from ready for either a long war or for the occupation of large areas of Africa.

Generale d’Armata Aerea Principe Amedeo, Duca d’Aosta, was appointed viceroy and governor general of Africa Orientale Italiana in November 1937, with his headquarters in Addis Ababa, the Ethiopian capital. On 1 June 1940, as commander-in-chief of the Comando Forze Armate dell’Africa Orientale Italiana, Aosta had about 290,476 metropolitan and local troops including naval and air force personnel. By 1 August, mobilisation had increased the number to 371,053 troops. On 10 June, the Italian army was organised in three corps-level and one divisional-level commands: the Settore Nord (northern sector) in Italian Eritrea with Generale di Corpo d’Armata Luigi Frusci in command at Asmara; the Settore Sud (southern sector) with Generale d’Armata Pietro Gazzera in command at Jimma, the Settore Orientale (eastern sector) with Generale di Corpo d’Armata Guglielmo Nasi in command at Addis Ababa, and the Settore Giuba (Giuba sector) with Generale di Corpo d’Armata Carlo de Simone in command at Mogadishu.

Aosta had two metropolitan divisions in the form of Generale di Divisione Giovanni Varda’s 40a Divisione fanteria 'Cacciatori d’Africa' and Generale di Divisione Antonio Calierno’s 65a Divisione fanteria 'Granatieri di Savoia', one battalion of Alpini (elite mountain troops), one Bersaglieri battalion of motorised infantry, several Milizia Coloniale 'Blackshirt' battalions, and a miscellany of smaller units. About 70% of Italian troops were locally recruited askari. The regular Eritrean battalions and the Regio Corpo Truppe Coloniali (Royal Corps of Somali Colonial Troops) were among the best Italian units in Africa Orientale Italiana and included Eritrean Penne di Falco (falcon feather) cavalry. Most of the Italian colonial troops were recruited, trained and equipped for repression of colonial insurgency, although the Somali dubats from the borderlands were useful light infantry and skirmishers. Irregular bande were hardy and mobile, knew the country and were effective scouts and saboteurs, although sometimes confused with shiftas, marauders who plundered and murdered at will.

Once Italy had entered the war, a 100-strong company was formed from German residents of East Africa and also from stranded German sailors.

The Italian forces in East Africa were equipped with about 3,313 heavy machine guns, 5,313 lighter machine guns, 24 M11/39 medium tanks, 39 L3/35 tankettes, 126 armoured cars, 824 pieces of artillery, 24 20-mm anti-aircraft cannon, 71 81-mm (3.2-in) mortars and 672,800 rifles. From June 1940, the Italians had little opportunity for reinforcement or supply, which led to severe shortages, especially of ammunition. On occasion, foreign merchant vessels captured by German merchant raiders in the Indian Ocean were brought to Somali ports but their cargoes were not always of much use to the Italian war effort. On 22 November 1940 the Yugoslav steamer Durmitor, captured by the German merchant raider Atlantis, put in at Warsheikh with a cargo of salt and several hundred prisoners.

The Comando Aeronautica Africa Orientale Italiana, commanded by Generale d’Armata Aerea Pietro Pinna Parpaglia at Addis Ababa, had three sector commands corresponding to the land fronts: these were the Comando Settore Aeronautico Nord, Comando Settore Aeronautico Est and Comando Settore Aeronautico Sud. In June 1940, the Commando Aeronautica Africa Orientale Italiana had 323 aircraft in 23 bomber squadrons with 138 aircraft, comprising 14 squadrons with six aircraft each, six Caproni Ca 133 three-engined light bomber squadrons, seven Savoia-Marchetti SM.81 three-engined medium bomber squadrons and two Savoia-Marchetti SM.79 three-engined medium bomber squadrons. Four fighter squadrons had 36 aircraft, comprising two squadrons each of nine Fiat CR.32 single-engined biplane aircraft and two squadrons each of nine Fiat CR.42 Falco single-engined biplane aircraft. There was one one reconnaissance squadron with nine IMAM Ro.37 single-engined biplane aircraft. The aircraft totals comprised 183 first line aircraft and 140 reserve aircraft, and of these 59 were operational and 81 were unserviceable.

On the outbreak of war, the Comando Aeronautica Africa Orientale Italiana had 10,500 tons of aviation fuel, 5,200 tons of bombs and 8.62 million rounds of ammunition. Aircraft and engine maintenance was conducted at the main air bases and at the Caproni and Piaggio workshops, which could repair about 15 seriously damaged aircraft and engines each month, along with some moderately and lightly damaged aircraft and could also recycle scarce materials. The Italians had reserves for 75% of their front-line strength but lacked spare parts and many aircraft were therefore cannibalised to keep others operational. The quality of the units varied. The SM.79 was the only modern bomber and the CR.32 fighter was obsolete, but the Comando Aeronautica Africa Orientale Italiana had a cadre of highly experienced veterans from the Spanish Civil War. There was also the nucleus of a transport fleet, with nine Savoia-Marchetti S.73, nine Ca.133, six Ca.148 (a lengthened version of the Ca.133) and one Fokker F.VII aircraft, and these were employed for internal communications and carried urgent items and personnel between sectors.

From 1935 to 1940 the Regia Marina laid plans for an ocean-going Flotta d’evasione (escape fleet) equipped for service in the tropics. The plans varied from three battleships, one aircraft carrier, 12 cruisers, 36 destroyers and 30 submarines to a more realistic two cruisers, eight destroyers and 12 submarines. Even the lower establishment proved too expensive and in 1940 the Flottiglia del mar rosso (Red Sea flotilla) had seven older fleet destroyers, the 5a Divisione cacciatorpediniere with the 'Leone' class destroyers Pantera, Tigre and Leone and the [e[3a Divisione torpediniere with the 'Sauro' class torpedo boats Francesco Nullo, Nazario Sauro, Cesare Battisti and Daniele Manin. There were also Orsini and Acerbi, which were two old local-defence torpedo boats and a squadron of five World War I motoscafi armati silurante motor torpedo boats. The Flottiglia del mar rosso had eight modern submarines (Archimede, Galileo Ferraris, Galileo Galilei, Torricelli, Galvani, Guglielmotti, Macallé and Perla).

The flotilla was based at Massawa in Eritrea on the Red Sea, and had been established to link Axis-occupied Europe and the naval facilities in the Italian concession zone at Tientsin in China. There were also limited port facilities at Assab in Eritrea and at Mogadishu in Italian Somaliland. When the Mediterranean route was closed to Allied merchant ships in April 1940, the Italian naval bases in East Africa were well placed for attacks on convoys en route to Suez up the east coast of Africa and through the Red Sea. The finite resources in Africa Orientale Italiana were intended to last for a war lasting about six months, and the primary task of the the submarine force was denial of the Red Sea route to the British.

The British had based forces in Egypt since 1882 but these were greatly reduced by the terms of the Anglo-Egyptian Treaty of 1936. A small British and commonwealth force garrisoned the Suez Canal and the Red Sea route, which was vital to communications with the British Indian Ocean, Far Eastern and Australasian components. In the middle of 1939, General Sir Archibald Wavell was appointed to lead the new Middle East Command with responsibility for the Mediterranean and Middle Eastern theatres. Wavell was responsible for the defence of Egypt through the commander of the British Troops Egypt, for the training of the Egyptian army and for the co-ordination of operations with the British naval command in the Mediterranean, Admiral Sir Andrew Cunningham, the commander of the East Indies Station, Vice Admiral R. Leatham, the commander in India, General Sir Robert Cassels, the inspector general of African Colonial Forces, Major General Douglas Dickinson, and the air commander in the Middle East, Air Chief Marshal Sir William Mitchell. (French divisions in Tunisia faced the Italian 5a Armata on the western Libyan border until the Franco-Axis armistice of 22 June 1940.) In Libya, the Italian army had about 215,000 men, and in Egypt the British had about 36,000 men, with another 27,500 training in Palestine. Wavell had about 86,000 men at his disposal for Libya, Iraq, Syria, Iran and East Africa.

The Middle East Command was established before the outbreak of war to control land operations and co-ordinate with the naval and air commands in the Mediterranean and Middle East. Wavell was allowed only five staff officers for plans and command of an area of 3.5 million sq miles (9.065 million km²). From 1940 to 1941, operations took place in the Western Desert of Egypt, East Africa, Greece and the Middle East. In July 1939, Wavell devised a strategy to defend and then to dominate the Mediterranean as a base from which to attack Germany through eastern and south-eastern Europe. The conquest of Italian East Africa came second only to the defence of Egypt and the Suez Canal. In August, Wavell ordered the rapid development of plans to gain control of the Red Sea. He specified a concept of offensive operations from Djibouti to Harar and then Addis Ababa or Kassala to Asmara then Massawa, preferably on both lines simultaneously. Wavell reconnoitred East Africa in January 1940 and the theatre was formally added to his responsibilities. He expected that the Somaliland colonies could be defended with minor reinforcement. If Italy joined the war, Ethiopia would be invaded as soon as there were sufficient troops. Wavell also co-ordinated plans with South Africa in March. On 1 May 1940, Wavell ordered British Troops Egypt to mobilise discreetly for military operations in western Egypt, but after the June debacle in France Wavell had to follow a defensive strategy.

After Italian operations in Sudan at Kassala and Gallabat in June, Prime Minister Winston Churchill blamed Wavell for a 'static policy'. Anthony Eden, the secretary of state for war, communicated to Wavell that an Italian advance toward Khartoum should be destroyed. Wavell replied that the Italian attacks were not serious but went to Sudan and Kenya to see for himself and met the Ethiopian emperor, Haile Selassie, at Khartoum. Here Eden convened a conference at the end of October 1940 with Selassie, South African General Jan Smuts (an advisor to Churchill), Wavell, Major General W. Platt (Sudan Defence Force) and Lieutenant General A. G. Cunningham (East African Forces). A plan to attack Ethiopia, including support for Ethiopian irregular forces, was agreed. In November 1940, the British gained an intelligence advantage when the Government Code and Cypher School broke the Italian army’s high-grade cypher in East Africa. Later in that same month, the replacement cypher for the Regia Aeronautica was broken by the Combined Bureau, Middle East.

During September 1940, Wavell ordered the commanders in Sudan and Kenya to make limited attacks once the rainy season had ended. On the northern front, Platt was to attack Gallabat and its vicinity, and on the southern front Cunningham was to advance to the north from Kenya through Italian Somaliland into Ethiopia. Early in November 1940, Cunningham had taken over the East African Force from Dickinson, who was in poor health. While Platt advanced from the north and Cunningham from the south, Wavell planned for a third force to be landed in British Somaliland by amphibious assault to retake the colony and then to advance into Ethiopia. The three forces were to meet at Addis Ababa. The conquest of Africa Orientale Italiana would thus remove the land threat to supplies and reinforcements coming from Australia, New Zealand, India, South Africa and British East Africa via the Suez Canal for the 'Campaign in the Western Desert' and reopen the over-land route from Cape Town to Cairo.

On 10 June 1940, Dickinson’s East Africa Force had been established for North-East Africa, East Africa and British Central Africa. In Sudan about 8,500 troops and 80 aircraft guarded a 1,200-mile (1930-km) frontier with Africa Orientale Italiana. Platt had 21 companies (4,500 men) of the Sudan Defence Force, and of these companies five (later six) were organised as motor machine gun companies. There was no artillery, but the Sudan Horse was converting to a 3.7-in (94-mm) mountain howitzer battery. The 1/Worcestershire Regiment, 1/Essex Regiment and 2/West Yorkshire Regiment were, in the middle of September, incorporated into Brigadier J. C. O. Marriott’s Indian 29^th Brigade, Brigadier W. J. Slim’s Indian 10^th Brigade and Brigadier A. G. O. M. Mayne’s Indian 9^th Brigade respectively of Major General L. Heath’s Indian 5^th Division when it arrived.

Major General N. M. Beresford-Peirse’s Indian 4^th Division was transferred from Egypt in December. The British had an assortment of armoured cars, and B Squadron of the 4^th Royal Tank Regiment with Matilda infantry tanks joined the Indian 4^th Division in January 1941. On the outbreak of hostilities, Colonel A. R. Chater in British Somaliland had about 1,754 men comprising the Somaliland Camel Corps and the 1/Northern Rhodesia Regiment. By August, the 1/2^nd Punjab and 3/5^th Punjab Regiments had been transferred from Aden and the 2/King’s African Rifles with the 1^st East African Light Battery (3.7-in/94-mm howitzers) came from Kenya, raising the total to 4,000 troops, in the first week of August. In the Aden Protectorate, the British Forces Aden (Air Vice Marshal G. M. R. Reid) had a garrison of the two Indian infantry battalions until they were transferred to British Somaliland in August.

In August 1939, Wavell had ordered a covert plan to encourage the rebellion in the western Ethiopian province of Gojjam, which the Italians had never been able to repress. In September, Colonel D. A. Sandford arrived to run the project, but until the Italian declaration of war, the conspiracy was held back by the government’s policy of appeasement. Mission 101 was formed to co-ordinate the activities of the Ethiopian resistance. In June 1940, Selassie arrived in Egypt and in July, went to Sudan to meet Platt and discuss plans to recapture Ethiopia, despite Platt’s reservations. In July, the British recognised Selassie as emperor, and in August Mission 101 entered Gojjam province to reconnoitre. Sandford requested that before the rainy season ended supply routes be established to the area north of Lake Tana and that Selassie should return in October as a catalyst for the uprising. Gaining control of Gojjam required the Italian garrisons to be isolated along the main road from Bahrdar Giorgis south of Lake Tana, to Dangila, Debra Markos and Addis Ababa to prevent them concentrating against the Arbegnoch (Amharic for 'patriots').

Italian reinforcements arrived in October and patrolled more frequently, just as dissensions among local potentates were reconciled by Sandford’s diplomacy. The Frontier Battalion of the Sudan Defence Force, established in May 1940, was joined at Khartoum by the 2^nd Ethiopian and 4^th Eritrean Battalions, which were raised from émigré volunteers in Kenya. Operational centres, each comprising one officer, five non-commissioned officers and several picked Ethiopians were formed and trained in guerrilla warfare to provide leadership cadres, and £1 million was set aside to finance operations. Major O. C. Wingate was sent to Khartoum with an assistant to join the headquarters of the Sudan Defence Force, and on 20 November Wingate was flown to Sakhala to meet Sandford. On this date, the RAF bombed Dangila, dropped propaganda leaflets and supplied Mission 101. This raised Ethiopian morale, which had suffered much from Italian air power since the 2^nd Italo-Abyssinian War. Mission 101 managed to persuade the Arbegnoch to the north of Lake Tana to spring several ambushes on the road linking Metemma and Gondar, and the Italian garrison at Wolkait was withdrawn in February 1941.

On 3 August 1940, the Italians invaded British Somaliland with two colonial brigades, four cavalry squadrons, 24 M11/39 medium tanks and L3/35 tankettes, several armoured cars, 21 howitzer batteries, pack artillery and air support. The British had a garrison of two companies of the Sudan Defence Force, two motor machine gun companies and one mounted infantry company. Kassala was bombed and then attacked, the British retiring slowly. On 4 August, the Italians advanced with a western column toward Zeila, de Simone’s central column toward Hargeisa and an eastern column toward Odweina in the south. The Somaliland Camel Corps skirmished with the advancing Italians as the main British force slowly retired. On 5 August, the towns of Zeila and Hargeisa were captured, isolating the British from French Somaliland. Odweina fell on the following day and the Italian central and eastern columns joined forces. On 11 August, Godwin-Austen was diverted to Berbera, en route to Kenya, to take command as reinforcements increased the British garrison to five battalions. Between 5 and 19 August, RAF squadrons based at Aden flew 184 sorties, dropped 60 tons of bombs, and lost seven aircraft destroyed and 10 damaged.

On 11 August, the Italians began the 'Battle of Tug Argan' (a tug is a dry, sandy riverbed), where the road from Hargeisa crosses the Assa hills, and by 14 August, the British were at risk of defeat in detail by the larger Italian force and its greater quantity of artillery. Close to being cut off and with only one battalion left in reserve, Godwin-Austen contacted Lieutenant General Sir Henry Maitland Wilson, commanding the British Troops in Egypt in Cairo (Wavell was in London) and was authorised to withdraw from the colony. The 2/The Black Watch, supported by two companies of the 2/King’s African Rifles and parties of the 1^st/2^nd Punjab Regiment, covered the retreat of the British contingent to Berbera.

By 14.00 on 18 August, most of the contingent had been evacuated to Aden, but the Australian light cruiser Hobart and the headquarters remained until the morning of 19 August before departing, and the Italians entered Berbera on the evening of 19 August. In the final four days of this little campaign, the RAF flew 12 reconnaissance and 19 reconnaissance/bombing sorties, with 72 attacks on Italian transport and troop columns, and 36 fighter sorties were flown over Berbera. The British lost 38 men killed and 222 wounded, whereas the Italians suffered 2,052 casualties. Their fuel and ammunition expenditures, and the wear and tear on vehicles, was difficult to remedy, and this compelled the Italians to switch to the defensive. Churchill criticised Wavell for abandoning the colony without enough fighting, but Wavell called it a textbook withdrawal in the face of superior numbers.

The Anglo-Egyptian Sudan shared a 1,000-mile (1610-km) border with Africa Orientale Italiana , and on 4 July 1940 was invaded from Eritrea by an Italian force of about 6,500 men, who advanced on the railway junction at Kassala. The Italians forced the British garrison of 320 men of the Sudan Defence Force and some local police to retire after inflicting casualties of 43 killed and 114 wounded for 10 casualties of their own. The Italians also drove a platoon of No. 3 Company of the Sudan Defence Force’s Eastern Arab Corps from the small fort at Gallabat, just over the border from Metemma, about 200 miles (320 km) to the south of Kassala, and took the villages of Qaysan, Kurmuk and Dumbode on the Blue Nile river. From there the Italians ventured no farther into Sudan as a result of their shortage of fuel and fortified Kassala with anti-tank defences, machine gun posts and strongpoints, later establishing a brigade-strong garrison. The Italians were disappointed to find little anti-British sentiment among the Sudanese population.

The Indian 5^th Division began to reach Sudan early in September 1940. The Indian 29^th Brigade was placed on the Red Sea coast to protect Port Sudan, the Indian 9^th Brigade was based to the south-west of Kassala, and the Indian 10^th Brigade was sent to Gedaref, with the divisional headquarters, to block an Italian attack on Khartoum from Goz Regeb to Gallabat, on a front of 200 miles (320 km). Colonel F. W. Messervy’s 'Gazelle' Force was created on 16 October as a mobile unit to raid Italian territory and delay an Italian advance.

Gallabat fort lay in Sudan and Metemma a short way across the Ethiopian border, beyond the 'Boundary Khor', a dry riverbed with steep banks covered by long grass. Both places were surrounded by field fortifications and Gallabat was held by a colonial infantry battalion. Metemma had two colonial battalions and a banda unit under the command of Tenente Colonnello Castagnola. The Indian 10^th Brigade, one field artillery regiment and B Squadron of the 6^th Royal Tank Regiment with seven Cruiser Mk I tanks and seven Light Tanks Mk VI, attacked Gallabat at 05.30 on 6 November. An RAF contingent of six Vickers Wellesley single-engined light bombers and nine Gloster Gladiator single-engined biplane fighters was deemed sufficient to overcome the 17 Italian fighters and 32 bombers believed to be in range. The infantry assembled between 1 and 2 miles (1.6 and 3.2 km) from Gallabat, whose garrison was unaware that an attack was imminent until the RAF bombed the fort and put its radio equipment out of action. The field artillery began a simultaneous bombardment, and after one hour the gunners changed targets and shelled Metemma. The previous night, the 4/10^th Baluch Regiment had occupied a hill overlooking the fort as a flank guard. The troops on the hill covered the advance at 06.40 of the 3/Royal Garwhal Rifles followed by the tanks. The Indians reached Gallabat and fought hand-to-hand with the 65a Divisione fanteria 'Granatieri di Savoia' and some Eritrean troops in the fort. At 08.00, the 25o Battaglione Coloniale and 77o Battaglione Coloniale counterattacked and were repulsed, but three British tanks were knocked out by mines and six by mechanical failure caused by the rocky ground.

The defenders at Boundary Khor were dug in behind fields of barbed wire and Castagnola had contacted Gondar for air support. Italian bombers and fighters attacked all day, shot down seven Gladiator fighters for a loss of five Fiat CR.42 fighters and destroyed the lorry carrying spare parts for the tanks. The ground was so hard and rocky that there were no trenches and when the Italian bombers made their largest attack, the infantry had no cover. An ammunition lorry was set on fire by burning grass and the sound was taken to be an Italian counterattack on the British rear. When a platoon advanced toward the sound with fixed bayonets, some troops thought that they were retreating. Part of the 1/Essex Regiment at the fort broke and ran, taking some of the Garwhalis with them. Many of the British fugitives mounted their transport and drove off, spreading the panic and some of the runaways reached Doka before being stopped.

The Italian bombers returned in the course of the next morning and Slim ordered a withdrawal from Gallabat ridge, 3 miles (4.8 km) to the west, to less exposed ground that evening. Sappers of the 21^st Field Company remained behind to demolish the remaining buildings and stores in the fort. The artillery bombarded Gallabat and Metemma, and ignited Italian ammunition dumps full of pyrotechnics. British casualties since 6 November had been 42 men killed and 125 wounded. The brigade patrolled to deny the fort to the Italians and on 9 November, two Baluch companies attacked and held the fort during the day and retired in the evening. During the night an Italian counterattack was repulsed by artillery fire, and on next morning the British reoccupied the fort unopposed. Ambushes were laid and prevented Italian reinforcements from occupying the fort or the hills on the flanks, despite frequent bombing by the Regia Aeronautica.

On the Italian declaration of war on 10 June 1940, Dickinson’s East Africa Force comprised two East African brigades of the King’s African Rifles organised as a Northern Brigade and a Southern Brigade comprising one reconnaissance regiment, one light artillery battery and the 22^nd Mountain Battery Royal Indian Artillery. By March 1940, the strength of the King’s African Rifles had reached 883 officers, 1,374 non-commissioned officers and 20,026 African other ranks. Wavell ordered Dickinson to defend Kenya and to pin down as many Italian troops as possible. Dickinson planned to defend Mombasa with the 1^st East African Brigade and to deny a crossing of the Tana river and the fresh water at Wajir with the 2^nd East African Brigade. Detachments were to be placed at Marsabit and Moyale, and at Turkana near Lake Rudolf, an arc of 850 miles (1370 km). The Italians were thought to have troops at Kismayu, Mogadishu, Dolo, Moyale and Yavello, which turned out to be colonial troops and bande, with two brigades at Jimma, ready to reinforce Moyale or attack Lake Rudolf and then invade Uganda. By the end of July, the 3^rd East African Brigade and the 6^th East African Brigade had been formed. A Coastal Division and a Northern Frontier District Division had been planned, but then Major General H. E. de R. Wetherall’s 11^th (African) Division and Godwin-Austen’s 12^th (African) Division were created instead in their place.

On 1 June, the first South African unit arrived in Mombasa, the main port of Kenya, and by the end of July, the South African 1^st Brigade Group had arrived. On 13 August, Major General G. L. Brink’s South African 1^st Division was formed and by the end of 1940, about 27,000 South Africans were in East Africa in the South African 1^st Division, the 11^th (African) Division and the 12^th (African) Division. Each South African brigade group consisted of three infantry battalions, one armoured car company and signal, engineer and medical units. By July, under the terms of a war contingency plan, the 2^nd (West Africa) Brigade, from the Gold Coast, and the 1^st (West Africa) Brigade, from Nigeria, were provided for service in Kenya by the Royal West African Frontier Force. The 1^st (West African) Brigade, the two East African brigades and some South African units, formed the 11^th (African) Division. The 12^th (African) Division had a similar establishment with the 2^nd (West African) Brigade.

At dawn on 17 June, the Rhodesians supported a raid by the Sudan Defence Force on the Italian desert outpost of El Wak in Italian Somaliland, about 90 miles (140 km) to the north-east of Wajir. The Rhodesians bombed and burned down thatched mud huts and generally harassed the Italian forces. As the main fighting at that time was against Italian advances toward Moyale in Kenya, the Rhodesians concentrated there. On 1 July, an Italian attack on the border town of Moyale, on the edge of the Ethiopian escarpment, where the tracks toward Wajir and Marsabit meet, was repulsed by a company of the 1/King’s African Rifles, and reinforcements were moved up. The Italians carried out a larger attack by about four battalions on 10 July, after a considerable artillery bombardment, and after three days the British withdrew unopposed. The Italians eventually advanced to the water holes at Dabel and Buna, nearly 62 miles (100 km) inside Kenya, but lack of supplies prevented any farther advance.

After their conquest of British Somaliland, the Italians adopted a more defensive posture. Late in 1940, Italian forces suffered defeats in the Mediterranean, the Western Desert, the Battle of Britain and in the Greco-Italian War. This prompted Generale d’Armata Ugo Cavallero, the new Italian chief-of-staff in Rome, to adopt a new strategy in East Africa. In December 1940, Cavallero thought that Italian forces in East Africa should abandon offensive action against the Sudan and the Suez Canal and concentrate on the defence of Africa Orientale Italiana. In response to Cavallero and Aosta, who had requested permission to withdraw from the Sudanese frontier, the army high command in Rome ordered Italian forces in East Africa to withdraw to better defensive positions.

Frusci was ordered to withdraw from Kassala and Metemma in the lowlands along the Sudan/Eritrea border and hold the more easily defended mountain passes on the roads linking Kassala and Agordat and between Metemma and Gondar. Frusci chose not to withdraw from the lowlands, however, as any such withdrawal would involve too great a loss of prestige and because Kassala was an important railway junction and its retention prevented the British from using the railway to carry supplies from Port Sudan on the Red Sea coast to the base at Gedaref. Information on the Italian withdrawal was quickly decrypted by the British, and Platt was able to begin his offensive into Eritrea on 18 January 1941, three weeks ahead of schedule.

In Sudan, the Air Headquarters Sudan (from 17 August the Headquarters No. 203 Group and from 19 October the Air Headquarters East Africa), subordinate to Air Chief Marshal Sir Arthur Longmore’s RAF Middle East command, had Nos 14, 47 and 223 Squadrons with Wellesley bombers. A flight of Vickers Vincent single-engined biplane aircraft of No. 47 Squadron performed army co-operation duties and were later reinforced from Egypt by No. 45 Squadron with Bristol Blenheim twin-engined light bombers. Six Gladiator biplane fighters were based in Port Sudan for trade protection and anti-submarine patrols over the Red Sea, the air defence of Port Sudan, Atbara and Khartoum, and for army support.

In May, No. 1 (Fighter) Squadron of the South African Air Force arrived, was transferred to Egypt to convert to the Gladiator and returned to Khartoum in August. The South African Air Force in Kenya comprised No. 12 Squadron (Junkers Ju 86 twin-engined medium bombers), No. 11 Squadron (Battle light bombers), No. 40 Squadron (Hawker Hartebeest single-engined general-purpose biplane aircraft), No. 2 Squadron (Hawker Fury single-engined biplane fighters) and No. 237 (Rhodesia) Squadron (Hawker Hardy single-engined general-purpose biplane aircraft). Better aircraft became available at a later date, but these initial aircraft were in general old and slow, the South Africans even pressing an old Vickers Valentia twin-engined biplane transport aerop’ane into service as an extemporised bomber.

The South Africans faced experienced Italian pilots, including a cadre of Spanish Civil War veterans as noted above. Despite its lack of experience, No. 1 Squadron claimed 48 Italian aircraft destroyed and 57 damaged in the skies over East Africa, together with another 57 claimed destroyed on the ground, for the loss of just six pilots, but it is believed with some justification that the squadron was guilty of severe over-claiming.

From November 1940 to a time early in January 1941, Platt continued to apply constant pressure on the Italians along the Sudan/Ethiopia border with patrols and raids by ground troops and aircraft. Hawker Hurricane single-engined monoplane fighters and more Gladiator biplane fighters began to replace some of the older models. On 6 December, a large concentration of Italian motor transport was bombed and strafed by commonwealth aircraft a few miles north of Kassala. The same aircraft then proceeded a low-level machine gun attack on the nearby positions of Italian 'Blackshirt' and colonial infantry. A few days later, the same aircraft bombed the Italian base at Keru, some 50 miles (80 km) to the east of Kassala, and the commonwealth pilots had the satisfaction of seeing supply dumps, stores and transport enveloped in flame and smoke as they flew away. One morning in the middle of December, a force of Italian fighters strafed a Rhodesian landing-strip at Wajir near Kassala, where two Hardy aircraft were caught on the ground and destroyed and 6,000 Imp gal (15540 litres) of fuel were set alight, four Africans being killed and 11 injured as they fought the fire.

The approaches to the Red Sea through the Gulf of Aden and the Bab el Mandeb are 17 miles (28 km) wide. With the Italian declaration of war on 10 June and the loss of French naval support in the Mediterranean after 22 June, the 1,400-mile (2255-km) long Red Sea passage to Suez became the main British sea route to the Middle East. To the south of Suez the British held Port Sudan, about halfway along the Sudanese coast, and the base at Aden, 120 miles (195 km) on the south-western tip of the Arabian peninsula to the east of Bab el Mandeb. The principal Italian naval force, under the command of Contrammiraglio Mario Bonetti, was based at Massawa in Eritrea, about 400 miles (645 km) to the north of Bab el Mandeb, well placed for the Flottiglia del mar rosso to attack Allied convoys.

British codebreakers of the Government Code and Cypher School deciphered Italian orders of 19 May, coded using C38m machines, for the secret mobilisation of the army and air force in East Africa. Merchant traffic was stopped by the British on 24 May, pending the introduction of a convoy system. Rear Admiral A. J. L. Murray’s Red Sea Force, operational at Aden since April with the light cruisers Liverpool (replaced by Leander) and Australian Hobart, was reinforced by the light anti-aircraft cruiser Carlisle, which sailed to the south with the BS.4 convoy, the 28^th Destroyer Flotilla (Khartoum, Kimberley, Kingston and Kandahar) and three sloops from the Mediterranean. The force was to conduct a blockade Africa Orientale Italiana in 'Begum', attack the Flottiglia del mar rosso, and protect the sea route between Aden and Suez.

On 6 June, the 'Azio' class minelayer Ostia used 470 mines to lay eight barrages off Massawa, and the destroyer Pantera laid 110 mines in two barrages off Assab on the following day. When Italy declared war on 10 June, Galileo Ferraris sailed for French Somaliland, Galileo Galilei for Aden, Galvani for the Gulf of Oman and Mecallé for Port Sudan. On 14 June Torricelli put to sea to relieve Galileo Ferraris, whose crew had been incapacitated by chloromethane poisoning from the refrigeration system. The crew of Macallé was also afflicted as the boat ran aground and was lost on 15 June. On 18 June, Galileo Galilei boarded and released the neutral Yugoslav steamship Dravo, and on the next day engaged the British armed trawler Moonstone off Aden. All but one officer of the Italian boat were killed by shell fire and Galileo Galilei was captured along with many documents including operational orders for four other Italian submarines.