'Operazione 'E' was the Italian invasion of Egypt against British, commonwealth and Free French forces (9/16 September 1940).

The invasion by the Italian 10a Armata, under the temporary leadership of Generale d’Armata Italo Gariboldi, the commander of the 5a Armata in western Libya as Generale d’Armata Mario Berti, its actual commander, was currently absent on leave, ended the border skirmishing on the frontier between Libya and Egypt and began the 'Western Desert Campaign' proper. The Italian strategy was to advance from Libya along the Egyptian coast to seize the Suez Canal. After numerous delays, the scope of the offensive was reduced to an advance as far as Sidi Barrani and the engagement of any British forces in the area.

The 10a Armata advanced about 65 miles (105 km) into Egypt against British screening forces of the 7^th Armoured Division’s 7^th Support Group, under the command of Brigadier William Gott, the main force remaining in the vicinity of Mersa Matruh, which was the principal British base in the Western Desert. On 16 September 1940, the 10a Armata came to a halt and assumed defensive positions round the port of Sidi Barrani. The British casualties had been 10 men killed, and the Italians had suffered the loss of 120 men. The Italian army was to wait in fortified camps, until engineers had built the Via della Vittoria (Victory Road) along the coast as an extension of the Via Balbia in northern Libya. The Italians began to accumulate supplies for an advance against the 7^th Armoured Division and the Indian 4^th Division at Mersa Matruh, about 80 miles (130 km) farther to the east.

On 8 December, before the 10a Armata was ready to resume its advance on Mersa Matruh, the British began 'Compass' (i), a five-day raid against the fortified Italian camps outside Sidi Barrani. The raid succeeded and the few units of the 10a Armata in Egypt that were not destroyed were forced into a hurried retreat. The British pursued the remnants of the 10a Armata along the coast to Sollum and across the border to Bardia, Tobruk, Derna, Mechili, Beda Fomm and El Agheila on the Gulf of Sirte. The British suffered casualties of 1,900 men killed and wounded during 'Compass' (i) and captured 133,298 Italian and Libyan prisoners, 420 tanks, more than 845 pieces of artillery, and many aircraft.

The eastern province of Libya, Cyrenaica had been an Italian colony since the Italo-Turkish War (1911/12), although local resistance continued until 1932. With Tunisia, a part of French North Africa to the west and Egypt to the east, the Italians had to defend both frontiers and established a North Africa Supreme Headquarters, under the command of the governor-general of Italian Libya, Maresciallo dell’Aria Italo Balbo. This new headquarters controlled Gariboldi’s 5a Armata in the west facing the French and Berti’s 10a Armata in the east facing the British. In the middle of 1940, these two armies had nine metropolitan divisions with an establishment of about 13,000 men each, three 'Blackshirt' divisions and two Libyan colonial divisions with an establishment of 8,000 men each. Reservists had been recalled in 1939, along with the usual call-up of new conscripts.

The British had based military forces in Egypt since 1882, but these had been greatly reduced by the terms of the Anglo-Egyptian Treaty of 1936. The surviving small British and commonwealth force garrisoned the Suez Canal and the Red Sea route, which were vital to British communications with its Far Eastern and Indian Ocean territories. Although ruled indirectly by the UK, Egypt remained technically neutral during the war. In the middle of 1939, General Sir Archibald Wavell was appointed to head the new Middle East Command for supervision of the Mediterranean and Middle East theatres. Until the Franco-Axis armistice of June 1940, French divisions in Tunisia faced the Italians on the western Libyan border, which forced the Italians to divide their strength in Libya to face possible threats from both the east and the west.

In Libya, the Italian army had about 215,000 men, and in Egypt the British had about 36,000 men, with another 27,500 men training in Palestine. The British forces included the Mobile Division (Egypt) commanded by Major General Percy Hobart, one of two British armoured training formations, which in mid-1939 was renamed the Armoured Division (Egypt) and on 16 February 1940 became the 7^th Armoured Division under the command of Major General Michael Creagh. The border between Egypt and Libya was defended by the Egyptian Frontier Force, and from 17 June 1940 by the headquarters of Major General Richard O’Connor’s 6^th Division, which assumed command of what was now the Western Desert Force, with instructions to drive the Italians back from their frontier posts and dominate the hinterland in the event of war. The 7^th Armoured Division, less the 7^th Armoured Brigade, assembled at Mersa Matruh and sent the 7^th Support Group forward towards the frontier as a covering force.

The RAF also moved most of its bombers closer to the frontier, and Malta was reinforced to threaten the Italian maritime supply route to Libya.

In Tunisia, the French had eight divisions, capable of only limited operations, and in Syria three poorly armed and trained divisions, with about 40,000 troops and border guards, were on occupation duties against the civilian population.

The Italian land and air forces in Libya greatly outnumbered those of the British in Egypt, but suffered from poor morale and were handicapped by some inferior equipment. In Italian East Africa were another 130,000 Italian and East African troops with 400 pieces of artillery, 200 light tanks and 20,000 trucks. Italy declared war on 10 June 1940.

The Western Desert is about 240 miles (390 km) long from Mersa Matruh in Egypt, westward to Gazala on the Libyan coast, and along the Via Balbia, the only paved road. The Sand Sea, 150 miles (240 km) inland, marks the southern limit of the desert at its widest at Giarabub and Siwa. In British parlance, the Western Desert came to include eastern Cyrenaica in Libya. From the coast, extending into the hinterland lies a raised, flat plain of stony desert about 500 ft (150 m) above sea level and which extends 120 to 190 miles (200 to 300 km) in depth until the Sand Sea. The region is inhabited by a small number of Bedouin nomads and the local wildlife includes scorpions, vipers and flies.

Bedouin tracks link wells and the more easily traversed ground. Desert navigation is by sun, star, compass and 'desert sense', the last being a good intuitive perception of the environment gained by experience. (When 'Operazione 'E'' began in September, Generale di Divisione Pietro Maletti’s Raggruppamento 'Maletti' lacked experience of desert conditions, became lost after departing Sidi Omar, disappeared and had to be found by reconnaissance aircraft.) In spring and summer, the days are miserably hot and the nights very cold. The sirocco (gibleh or ghibli) hot desert wind blows clouds of fine sand, reducing visibility to a few yards and coating eyes, lungs, machinery, food and equipment. Motor vehicles and aircraft need special oil and air filters and the barren ground means that water and food as well as military stores, have to be transported from outside.

In 1936, Generale d’Armata Alberto Pariani had been appointed chief-of-staff of the Italian army and began a reorganisation of divisions to fight wars of rapid decision, according to current military thinking that speed, mobility and new technology could revolutionise military operations. In 1937, the well-established three-regiment organisation of divisions began to change to a two-regiment organisation as part of a 10-year plan to reorganise the standing army into 24 two-regiment, 24 three-regiment, 12 mountain, three motorised and three armoured divisions. The effect of the change was to increase the army’s administrative overhead but no corresponding increase in effectiveness. New technology such as tanks, motor vehicles and wireless communications were slow to arrive and were inferior to those of potential opponents. The dilution of the officer class to find extra unit staffs was made worse by the politicisation of the army and the addition of 'Blackshirt' Fascist militia. The reforms also promoted the tactics of frontal assault to the exclusion of other theories of war, dropping the emphasis on fast, mobile warfare backed by artillery. By September 1939, 16 of the Italian army’s 67 divisions, excluding the garrison of Ethiopia, had been converted to the two-regiment standard and had received their establishment of arms and equipment. The remaining divisions had obsolete equipment and no stock of replacements, and lacked artillery, tanks, anti-tank guns, anti-aircraft guns and transport.

Morale was deemed to be high and the army had recent experience of military operations. The Italian navy had prospered under the Fascist regime, which had paid for fast, well-built and well-armed ships as well as a large submarine fleet, but the navy lacked experience and training. The air force had been ready for war in 1936 but had since stagnated and was not considered by the British to be capable of maintaining a high rate of operations. The 5a Armata in Tripolitania, the western half of Libya opposite Tunisia, had eight divisions, and the 10a Armata had six infantry divisions to garrison the province Cyrenaica in the east. At the end of June, after the fall of France, four divisions were transferred from the 5a Armata to the 10a Armata, and when Italy declared war the 10a Armata comprised the 1a Divisione libica on the frontier from Giarabub to Sidi Omar and Generale di Corpo d’Armata Lorenzo Dalamazzo’s XXI Corpo d’Armata was deployed from Sidi Omar to the coast, Bardia and Tobruk. The XX Corpo d’Armata was moved to a position lying to the south-west of Tobruk, as a counter-offensive force.

Before the war’s start, Balbo had expressed his concerns to Mussolini and demanded more equipment including 1,000 trucks, 100 water tankers, more medium tanks and additional numbers of anti-tank guns, which the Italian economy could not produce or the army transfer from elsewhere. In Rome, Maresciallo d’Italia Pietro Badoglio, the chief-of-staff, fobbed him off with promises that 'When you have the 70 medium tanks you will dominate the situation' even as Balbo prepared to invade Egypt on 15 July. After Balbo had been killed in an accident, Mussolini replaced him with Graziani, with orders to attack Egypt by 8 August. Graziani replied that the 10a Armata was not properly equipped and that an attack could not possibly succeed, but Mussolini nonetheless ordered him to attack.

The ten divisions of Berti’s 10a Armata were subordinated to Generale do Corpo d’Armata’s XX Corpo d’Armata, Generale di Corpo d’Armata Ferdinando Cona’s XXI Corpo d’Armata, Generale di Corpo d’Armata Enrico Mannella’s XXII Corpo d’Armata and Generale di Corpo d’Armata Annibale Bergonzoli’s XXIII Corpo d’Armata. The army comprised a number of metropolitan infantry divisions, 'Blackshirt' divisions and Libyan colonial divisions. The XXI Corpo d’Armata had the 62a Divisione fanteria 'Marmarica' and 63a Divisione fanteria 'Cirene', 1a CCNN Divisione '23 Marzo', the 1a Divisione libica and 2a Divisione libica under the command of General di Corpo d’Armata Sebastiano Gallina, and the Raggruppamento 'Maletti', and with these was to undertake Operazione 'E'. Bergonzoli had available to is force about 1,000 trucks, first to move the 62a Divisione fanteria 'Marmarica' and 63^rd Divisione fanteria 'Cirene'. followed by the 1^st CCNN Divisione '23^rd Marzo'. The Libyan divisions had 650 vehicles, enough to move equipment, weapons and supplies, but the infantry would have to march; the Raggruppamento 'Maletti' had 450 vehicles, enough to move its troops. The Raggruppamento 'Maletti' comprised three battalions of Libyan infantry, additional artillery, much of the Italian armoured vehicle element in Libya and almost all of the M11/39 medium tanks. The XXI Corpo d’Armata, with the 61a Divisione fanteria 'Sirte' and the 2a CCNN Divisione '28 Ottobre', constituted the army’s reserve, and the XXII Corpo d’Armata, with the 64a Divisione fanteria 'Catanzaro' and 3a CCNN Divisione '3 Gennaio', were left at Tobruk for lack of transport.

Operational commands of the Regia Aeronautica were designated as Zona Aerea Territoriale, Squadra or Comando depending on the size and importance of the area in which they were operating. The 10a Armata was supported by the 5a Squadra Aerea with 336 aircraft in four bomber wings, one fighter wing, three fighter groups, two reconnaissance groups and two squadrons of colonial reconnaissance aircraft comprising 110 Savoia-Marchetti SM.79 three-engined medium bombers, fifty Breda Ba.65 single-engined ground attack aircraft, 170 Fiat CR.42 single-engined fighters and six IMAM Ro.37, Caproni Ca.309 and Caproni Ca.310bis long-range reconnaissance aircraft. On 9 September, another 64 bombers, 75 ground-attack aircraft and 15 reconnaissance aircraft arrived from Italy. The 5a Squadra Aerea was organised to follow and support the army in the field as a self-contained formation.

Berti could expect little support from the Regia Marina because 10 submarines had been lost since Italy declared war, the fleet was too important as a 'fleet in being' to risk, and was short of fuel.

Three times deadlines were set for the Italian invasion and cancelled; the first plan was intended to coincide with an expected German invasion of England on 15 July 1940. Balbo took all the trucks from the 5a Armata and the M11/39 medium tanks being delivered from Italy to reinforce the 10a Armata for a crossing of the frontier wire and an occupation of Sollum as soon as war was declared. After a British counterattack had been repulsed and the Italian armies had been replenished, the advance would continue. Although this plan was based on a realistic appreciation of what the Italian armies in Libya could achieve, it fell through when the German invasion of England was cancelled. It is worth noting that the Italians considered forming a mechanised force for the invasion of Egypt, followed by garrison troops to maintain the lines of communication. Two divisions and a brigade of Libyan troops could be fully motorised and join the tanks, together with motorised artillery, to create an all-arms force. Graziani rejected the suggestion since the rest of the army would thus have lost its supply transport. Generale di Divisione Valentino Babini’s Comando Carri Armati della Libia (tank command Libya), three or four artillery regiments and a motorised infantry division could have been formed according to the new mechanised warfare theory, but Graziani favoured strength in numbers.

The second plan, for 22 August, was for a limited eastward advance to Sollum and Shawni el Aujerin, with three columns moving on three axes of advance. Once Sollum had been occupied, an advance on Sidi Barrani would be considered, an example of advance-in-mass as used by the Italians on the northern front in the Ethiopian War. The Italian non-motorised infantry divisions were to use the only road. The summer heat in August, which would have affected the infantry very adversely, led to another postponement.

The third plan was for an invasion on 9 September with Sidi Barrani as the objective, and Graziani disclosed this plan to his staff six days before Mussolini ordered the invasion. The non-motorised metropolitan divisions were to advance along the coast and attack through the Halfaya Pass, occupy Sollum and continue to Sidi Barrani. A southern column of the Libyan divisions and the Raggruppamento 'Maletti' was to advance along the track linking Dayr al Hamra, Bir ar Rabiyah and Bir Enba in order to outflank the British on the escarpment. The Ragguppamento 'Maletti' was to drive to the south and east through the desert, but the Italian staff failed to provide proper maps and navigation equipment, and while moving to its assembly and jumping-off points, became lost and headquarters of the XXIII Corpo d’Armata had to send aircraft to help lead the group into position. The Libyan divisions arrived late at the rendezvous near Fort Capuzzo.

The embarrassment of the Raggruppamento 'Maletti' increased the Italian concerns about the 10a Armata's shortage of trucks and transport aircraft and the British domination of the terrain, and this resulted in another change of plan. The fourth plan was set for 13 September, with Sidi Barrani and the area to its south as the objective. The 10a Armata, with only five divisions as a result of the shortage of transport and the tanks of the Ragguppamento 'Maletti', were to advance in mass along the coast road, occupy Sollum and advance through Buq Buq to Sidi Barrani. The 10a Armata was then to consolidate at Sidi Barrani and bring up supplies, destroy any British counterattack and resume the advance to Mersa Matruh. The marching infantry divisions were to use the coast road because they would be ineffective anywhere else. A similar operation had been conducted on the northern front in Ethiopia, but was now contrary to mobile warfare theory, for which there were, in fact ample forces. Graziani believed the only way to defeat the British was by mass, having overestimated their strength.

Against an estimated 250,000 Italian troops in Libya and about 250,000 more in Italian East Africa, Wavell had a ration strength of about 36,000 troops in Egypt. These comprised 14 unbrigaded British infantry battalions; Major General Bernard Freyberg’s New Zealand 2^nd Division with one infantry brigade, one understrength cavalry regiment, one machine gun battalion and one field artillery regiment; Major General Noel Beresford-Peirse’s Indian Indian 4^th Division with two brigades and some artillery; and Major General Michael Creagh’s 7^th Armoured Division with two armoured brigades each containing two rather than three armoured regiments. The 7^th Support Group, with three motorised infantry battalions, artillery, engineers and machine gun units, was to harass the Italians and fight delaying actions between the border and Mersa Matruh if attacked, but to retain the capacity to engage the main Italian force.

At Mersa Matruh an infantry force would await the Italian attack, while from the escarpment on the desert flank the bulk of the 7^th Armoured Division, would be ready to counterattack. The covering force was to exaggerate its size and the 7^th Support Group was to use its mobility to cover the desert flank, while along the coast road, the 3/Coldstream Guards, one company of the 1/King’s Royal Rifle Corps and one company of Free French motorised marines, with supporting artillery and machine gun units, was to fall back in stages, demolishing the road as they retired. At the end of May 1940, the Royal Air Force in the Middle East had 205 aircraft, including 96 obsolete Bristol Bombay twin-engined medium bombers and modern Blenheim light bombers, 75 obsolete Gloster Gladiator single-engined fighters and 34 other types. In July, four Hawker Hurricane single-engined fighters arrived, but only one could be spared for the Western Desert Force. By the end of July, the Mediterranean Fleet controlled the Eastern Mediterranean and was able to bombard Italian coastal positions and transport supplies along the coast to Mersa Matruh and beyond.

On 17 June, using the headquarters of the British 6^th Division, the headquarters of O’Connor’s Western Desert Force was established to control all troops facing the Italians in Cyrenaica: the British totalled about 10,000 men, with aircraft, tanks and guns. O’Connor was ordered to organise aggressive patrolling along the frontier and set out to dominate no-man’s land by creating 'jock columns', which were mobile combined-arms units based on elements of the 7^th Armoured Division. These small but well-trained regular forces made the first attacks on Italian convoys and fortified positions across the border. British patrols closed up to the frontier wire on 11 June, with orders to dominate the area, harass the garrisons of the frontier forts and lay ambushes along the Via Balbia and inland tracks.

Some Italian troops were unaware that war had been declared, and 70 men were taken prisoner on the track to Sidi Omar. Patrols ranged north to the coast road between Bardia and Tobruk, west to Bir el Gubi and south to Giarabub. Within a week, the 11^th Hussars (Prince Albert’s Own) had seized Fort Capuzzo and at an ambush east of Bardia, captured the 10a Armata's chief engineer, Generale di Brigata Romolo Lastrucci. Italian reinforcements arrived at the frontier, began to conduct reconnaissance patrols, improved the frontier defences and recaptured Fort Capuzzo. On 13 August, the British raids were stopped to conserve the serviceability of vehicles, and the 7^th Support Group took over to observe the border wire for 60 miles (100 km) between Sollum and Fort Maddalena, ready to fight delaying actions if the Italians invaded Egypt.

The XXIII Corpo d’Armata was earmarked to lead the 10a Armata's attack to Sidi Barrani in Egypt along the coast road with non-motorised and motorised formations. The corps had been given more lorries: the 62a Divisione fanteria 'Marmarica' and 63a Divisione fanteria 'Cirene were partially motorised, the 1a CCNN Divisione '23 Marzo' was fully motorised, as were the Raggruppamento 'Maletti' and the the 1o Raggruppamento Carri (tank group). The part-motorised infantry divisions were to move by shuttling forward and the non-motorised infantry would have to march the 60 miles (100 km) to Sidi Barrani. Bergonzoli wanted the 1o Raggruppamento Carri as an advanced guard, two motorised infantry divisions in line and one motorised division in reserve. The two non-motorised Libyan divisions would have to move on foot, with the Raggruppamento 'Maletti' bringing up the rear. The 1o Raggruppamento Carri was held in reserve, except for the 62o Battaglione di Carri Armati (leggero) attached to the 63a Divisione fanteria and the 63o Battaglione di Carri Armati (leggero) to the 62a Divisione fanteria. The 2o Raggruppamento Carri remained at Bardia with the exception of its 9o Battaglione di Carri Armati (leggero) attached to the 2a Divisione libica. The 2o Battaglione di Carri Armati (medio) was with the Raggruppameto 'Maletti', which had three fully motorised Libyan infantry battalions.

On 9 September, Regia Aeronautica activity increased, and bombers from the RAF’s Nos 55, 113 and 211 Squadrons retaliated with attacks on Italian airfields, transport, supply dumps, and a raid on Tobruk by 21 aircraft. Later in the day, 27 Italian fighters made a sweep over Buq Buq and the RAF flew more sorties against Italian airfields. British air reconnaissance revealed much ground movement at Bardia, Sidi Azeiz, Gabr Saleh and in the direction of Sidi Omar, on the border wire, from the west, which was interpreted as the beginning of the Italian invasion. The 10a Armata's forward move swiftly revealed the limits of Italian mobility and navigation as the Raggruppamento 'Maletti' lost its way, as noted above, as it moved up to Sidi Omar. On 10 September, the armoured cars of the 11^th Hussars spotted the Raggruppamento 'Maletti' and a thick mist shielded the British as they shadowed the slow Italian assembly. As the mist cleared, the hussars were attacked by Italian aircraft, tanks and artillery.

On 13 September the 1a CCNN Divisione retook Fort Capuzzo and a bombardment fell on Musaid, just over the Egyptian side of the border, which was then occupied. Artillery fire on and bombing of Sollum airfield and barracks, which were empty, then began and raised a dust cloud. When this latter cleared, the Italian force could be seen drawn up, ready to advance against the British covering force of the 3/Coldstream Guards, some field artillery, one extra infantry battalion and one machine gun company. The Italians advanced along the coast with two divisions in he van behind a screen of motorcyclists, tanks, motorised infantry and artillery. The Italian formation made an easy target for artillery and aircraft, but the 1a Divisione libica soon occupied Sollum barracks and began to move down the escarpment to the port.

On the inland plateau, an Italian advance toward the Halfaya Pass was opposed by a covering force of one company of the 3/Coldstream Guards, one platoon of the Northumberland Fusilier and some artillery, which began to withdraw in the afternoon as more Italian infantry and tanks arrived.[35] During the evening, two columns of the 2a Divisione libica, 63a Divisione fanteria and Raggruppamento 'Maletti' from Musaid and the 62a Divisione fanteria from Sidi Omar converged on the pass. On the following day, the Italian units on the escarpment began to descend through the pass toward the Italian force advancing along the road from Sollum. A squadron of the 11^th Hussars, the 2^nd Rifle Brigade and cruiser tanks of the 1^st Royal Tank Regiment harassed the Italian force on the escarpment. Just after 12.00, the British troops on the coast retreated to Buq Buq and met reinforcements from the 11^th Hussars and one motorised company of the Troupes de marine (French marines), which was enough to maintain contact with the Italians. The British withdrew to Alam Hamid on 15 September and Alam el Dab on the next day, trying to inflict maximum losses without being pinned down, and destroying the coast road as they went: this damage was quickly made worse by the quantity of Italian traffic.

The uncommitted part of the 1o Raggruppamento Carri followed the 1a Divisione libica and the 2a Divisione libica toward Bir Thidan el Khadim. At Alam el Dab, near Sidi Barrani, about 50 Italian tanks, motorised infantry and artillery tried an outflanking move that forced the Coldstream Guards to retreat. The armoured group was engaged by British field artillery and made no further move, but by thearrival of night the 1a CCMM Divisione had occupied Sidi Barrani. Above the escarpment, the British covering forces fell back in parallel with those on the coast road. and the threat from the desert flank did not materialise. British aircraft flew many reconnaissance and bombing sorties and the 5a Squadra Aerea made sweeps with up to 100 fighters and bombers on British forward airfields and defensive positions. The British anticipated that the Italian advance would come to a halt at Sidi Barrani and Sofafi, and began to observe the positions with the 11^th Hussars, as the 7^th Support Group withdrew to rest and the 7^th Armoured Division prepared to confront an advance on Mersa Matruh. Italian radio broadcasts about the invasion suggested that the advance would continue from Sidi Barrani, but it soon appeared that the Italians were preparing defensive positions on an arc to the south and south-west at Maktila, Tummar (East), Tummar (West), Nibeiwa and on top of the escarpment at Sofafi as divisions farther to the rear occupied Buq Buq, Sidi Omar and Halfaya Pass.

The 10a Armata had advanced about 12 mi (19 km) per day to enable the non-motorised units to keep up, and at Sidi Barrani built fortified camps. No bold mechanised strokes or flanking movements had been made by the armoured units, the XXIII Corpo d’Armata had guarded the infantry instead and the 10a Armata suffered fewer than 550 casualties its advance. The Raggruppamento 'Maletti', the 1o Raggruppamento Carri and the 1a CCNN Divisione had failed to operate according to Italian armoured warfare theory. Lack of preparation, training and organisation had led to blunders in assembling and directing the Raggruppamento 'Maletti', and over-caution with the other tank battalions of 1o Raggruppamento Carri. The rushed motorisation of the 1a CCNN Divisione, which had not been trained as a motorised formation, disorganised the relationship between drivers and infantry.

The Italian advance had reached Sidi Barrani with only modest losses, but failed to do much damage to the British. On 21 September, there were 68 Fiat M11/39 medium tanks left of the 72 sent to Libya. The 1° Battaglione Carri Medi had nine serviceable and 23 unserviceable medium tanks and the [2]2o Battaglione Carri Medi had 28 operational and eight non-operational tanks. The Italian medium tank strength was expected to increase when deliveries began of the new Fiat M13/40, which had a powerful Cannone da 47/32 47-mm gun. The 2o Battaglione Carri Medi, with 37 M13/40 tanks, arrived in Libya early in October, followed by the 5o Battaglione Carri Medi with 46 M13/40 tanks on 12 December. In the middle of November the Italians had 417 medium and light tanks in Libya and Egypt.

Repair work began on the coast road, renamed the Via della Vittoria, from Bardia and construction of a water pipe was started, but neither was expected to be ready before the middle of December, after which the advance would be resumed as far as Mersa Matruh.

On 26 October, wrote that 'Forty days after the capture of Sidi Barrani I ask myself the question, to whom has this long halt been any use – to us or to the enemy? I do not hesitate to answer, it has been of much use, indeed, more to the enemy. It is time to ask whether you [Graziani] feel you wish to continue to command,' and two days later, on 28 October, the Italians invaded Greece, beginning the Greco-Italian War. Graziani was allowed to continue planning at a leisurely pace and an Italian advance to Mersa Matruh was scheduled for the middle of December.

On 17 September, the Mediterranean Fleet began to harass Italian communications and Benghazi harbour was mined. A destroyer and two merchant ships were sunk by torpedo and a destroyer hit a mine at Benghazi and sank. RAF Blenheim light bombers destroyed three aircraft on the ground at Benina. The road on the escarpment near Sollum was bombarded by a British gunboat and two British destroyers attacked targets near Sidi Barrani, from which fires and explosions were seen. Captured Italians spoke of damage, casualties and a loss of morale. An attempt to bombard Bardia by the cruiser Kent and two destroyers was thwarted by Italian torpedo bombers, which hit Kent's stern and put the ship out of action. Bombardments continued during the lull, which led to camps and depots being moved inland. Small British land columns were created to work with armoured car patrols, moving close to the Italian camps, gleaning information and dominating the vicinity.

On 8 December the British began the 'Compass' five-day raid against the fortified Italian camps set up in a defensive line outside Sidi Barrani. Berti was on sick leave and Gariboldi had temporarily taken his place. The raid succeeded and the few units of the 10a Armata in Egypt which were not destroyed were forced to withdraw. By 11 December, the British began a counter-offensive and the rest of the 10a Armata was swiftly defeated. The British pursued the remnants of the 10a Armata to Sollum, Bardia, Tobruk, Derna, Mechili, Beda Fomm and El Agheila on the Gulf of Sirte. The British lost 1,900 men killed and wounded, about one-tenth of their infantry, but captured 133,298 Italian and Libyan prisoners, 420 tanks and more than 845 guns and aircraft. The British were unable to continue beyond El Agheila as a result of very low vehicle serviceability and the diversion of the best-equipped formations and units to Greece.