The 'Battles of the Border Wire' is a portmanteau phrase for the battles fought between Axis and Allied forces on the 168-mile (271-km) obstacle in the Italian province of Libya along the length of the border of British-held Egypt, running from El Ramleh, in the Gulf of Sollum between Bardia and Sollum, south to Jaghbub parallel with the 25^th meridian east, the Libya/Egypt and the Libya/Sudan borders (11 June 1940/22 March 1941).

The border wire and its line of covering forts was built in eastern Libya by the Italians during the 2^nd Italo-Senussi War (1923/31) as a defensive system to contain the Senussi population, who crossed from Egypt during their resistance against Italian colonisers.

From the Italian declaration of war on 10 June 1940 until the conquest of Libya by the British in 1942, it was the scene of military engagements between Italian, British and German forces as the fighting ebbed and flowed across the border. While the installation was reasonably effective against the poorly equipped Senussi, it was ineffective against the well-equipped conventional army fielded by the British.

In 1922, the Italian Fascist leader Benito Mussolini continued the so-called Riconquista (reconquest) of Libya in the 2^nd Italo-Sanussi War. The border wire barrier was built by the Italian army under Generale di Corpo d’Armata Rodolfo Graziani, the vice-governor of Cyrenaica, in the early 1930s, to repress Senussi resistance against Italian colonisation, by hindering the movement of Senussi fighters and materials from Egypt. The barrier comprised four lines of stakes, each 5.6 ft (1.7 m) high, in concrete bases and laced with barbed wire in a line 200 miles (320 km) long, just inside the border from El Ramleh on the Gulf of Sollum, past Fort Capuzzo to Sidi Omar, then south, slightly to the west of the 25^th meridian east, the border with Egypt and Sudan. Three large forts at Amseat (Fort Capuzzo), Scegga (Fort Maddalena) and Giarabub, and six smaller forts at El Ramleh on the Gulf of Sollum, Sidi Omar, Sceferzen, Vescechet, Garn ul Grein and El Aamara were also built along the wire. The wire was patrolled by aircraft and armoured cars from the forts, by the Italian army and border guards, who attacked anyone seen in the frontier zone.

(Soon after the frontier wire system had been completed, the Italian colonial administration deported the people of the Jebel Akhdar to deny the rebels local support. More than 100,000 people were imprisoned in concentration camps at Suluq and El Agheila, where up to one-third of the Cyrenaican population died in squalor. The Senussi leader, Omar Mukhtar, was captured and killed in 1931, after which the resistance faded away apart from the followers of Sheik Idris, Emir of Cyrenaica, who went into exile in Egypt.)

British patrols closed up to the border wire on 11 June 1940 and began to dominate the area, harass the garrisons of the frontier forts and set ambushes along the Via Litoranea Libica (renamed Via Balbia later in 1940) and inland tracks. Some Italian troops were unaware that war had been declared and 70 men were captured during the day on the track to Sidi Omar. British patrols ranged as far to the north as the Via Litoranea Libica, on the coast between Bardia and Tobruk, to the west as Bir el Gubi and to the south as Giarabub. Italian reinforcements then arrived, began to reconnoitre, improved the border defences and recaptured Fort Capuzzo. On 13 August, the British raids were stopped to conserve the serviceability of vehicles and the Support Group of the 7^th Armoured Division assumed the task of observing the wire for some 60 miles (100 km) from Sollum to the south as far as Fort Maddalena, ready to fight delaying actions against an Italian advance.

Fort Capuzzo (Ridotta Capuzzo) was one of the forts built near the frontier with Egypt and the border wire. The Via Litoranea Libica ran to the south from Bardia to Fort Capuzzo, 8 miles (13 km) to the west of the port of Sollum in Egypt, then to the east across the frontier, down the escarpment to the coast. The fort was built with four crenellated stone walls around a yard with living quarters round it. A track ran to the south from the fort, just to the west of the border wire and the border, to Sidi Omar, Fort Maddalena and Giarabub.

On 14 June, four days after the Italian declaration of war on the UK and France, the 7^th Hussars and elements of the 1^st Royal Tank Regiment, supported by Gloster Gladiator single-engined biplane fighters of the RAF’s No. 33 Squadron and Bristol Blenheim twin-engined light bombers of No. 211 Squadron captured Fort Capuzzo as the 11^th Hussars took Fort Maddalena, about 60 miles (97 km) farther to the south.

The fort was not in British hands for long as the result of a lack of troops and equipment, but demolition parties visited each night to destroy Italian ammunition and vehicles. The Italians reoccupied Fort Capuzzo and held it with part of Luogotenente Generale Francesco Argentino’s 2a CCNN Divisione '28 Ottobre'). On 29 June, the Gruppo 'Maletti' repulsed British tanks with its artillery and then defeated a night attack. During the border skirmishes from 11 June to 9 September, the British claimed to have inflicted 3,500 casualties on the Italians for the loss of only 150 of their own men. On 16 December, during 'Compass' (i) (9 December 1940/9 February 1941), the 4^th Armoured Brigade of the Western Desert Force captured Sidi Omar and the Italians withdrew from Sollum, Fort Capuzzo and the other frontier forts. No. 9 Field Supply Depot was then established at the fort for the 7^th Armoured Division.

The fortified camp at Sidi Omar was ringed with barbed wire, trenches and minefields. On 11 June 1940, the 11^th Hussars in Rolls-Royce and Morris CS9 armoured cars reached the border wire, crossed during the night and exchanged fire with the garrison at Sidi Omar. Sidi Omar was captured on 16 December during 'Compass' (i) by the 7^th Hussars, 2^nd Royal Tank Regiment and the 4^th Royal Horse Artillery. The British shelled the fort, then the tanks charged the fort and one broke through the wall. After a second tank had driven through the hole in the wall, the garrison began to surrender. The Italians had concentrated their firepower on the eastern wall facing Egypt and had been surprised by an attack from the west. The Italian loss of the fort left the way clear for the British to send reinforcements and supplies to their forces farther to the north on the coast, free from the threat of attack from the inland flank.

On 16 June, two days after the loss of Fort Capuzzo and Fort Maddalena and six days after the Italian declaration of war, the 10a Armata created Colonnello Lorenzo d’Avanzo’s Raggruppamento d’Avanzo for the task of ending British penetrations of the border wire near Fort Capuzzo. The Raggruppamento 'd’Avanzo' comprised one motorised battalion of the 1a Divisione libica, one company of the 9o Battaglione di Carri Armati Leggeri with 16 L3/33 tankettes, one battery of four 77-mm (3.03-in) guns and 30 trucks. The Raggruppamento 'd’Avanzo' was sent from Gabr Saleh toward the area from Sidi Omar to Fort Capuzzo in order clear the area of British raiding parties. As the Raggruppamento 'd’Avanzo' advanced toward Fort Capuzzo in two columns, British forces in the vicinity were ordered to withdraw across the border.

Two armoured cars of the 11^th Hussars attacked the Italian column at Nezuet Ghirba, about 18 miles (29 km) to the west of Sidi Omar, in an area lacking any form of cover, along the route of the smaller Italian column. d’Avanzo formed a defensive square, with the four guns at the corners, the infantry along the sides and the 12 L3 tankettes patrolling outside. The British reinforced the 11^th Hussars with the armoured cars of the 7^th Hussars and a mixed force of light tanks, one squadron of Cruiser Mk I tanks and one battery of artillery. The Italian tanks charged forward ahead of the artillery and infantry, and were knocked out. The British then circled the Italian square, firing at the trucks and infantry, and after the second circuit the Italian artillery opened fire. The Italian gunners had only high explosive ammunition and the British concentrated on the guns at each corner. Lacking cover, the Italian gunners were soon shot down and then the infantry broke. The British destroyed 12 tankettes and the four pieces of light artillery, and killed or took prisoner 100 of the 400 Italian infantrymen.

A Squadron of the 11^th Hussars made three gaps in the wire on the night of 11 June, cut telephone poles on the Italian side and skirmished around the fort. On 13 June, a troop of armoured cars attacked the fort and was repulsed by the garrison, and was then attacked by Italian aircraft as it fell back. The 11^th Hussars reconnoitred again on 14 June, with part of the 4^th Armoured Brigade ready to attack, but the garrison surrendered, the British taking 18 men prisoner and destroying equipment before moving to set an ambush on the Via Litoranea Libica.

The 'Siege of Giarabub' (now Jaghbub) took place between the Western Desert Force and the Italian garrison. In the aftermath of 'Operazione 'E'', the Italian invasion of Egypt by the 10a Armata between 9 and 16 September, the 'Compass' (i) operation (9/16 December) by the Western Desert Force, the 'Battle of Sidi Barrani' and the pursuit of the 10a Armata into Cyrenaica (16 December 1940/9 February 1941), the fortified Italian position at the Al Jaghbub oasis was besieged by part of the Australian 6^th Division from December 1940 to 21 March 1941. The Australian 6^th Divisional Cavalry Regiment started the siege in December 1940 and isolated the oasis, leaving the garrison dependent on the Regia Aeronautica for the air delivery of supplies. Air transport proved insufficient and hunger prompted many of the locally recruited troops to desert. After being reinforced by the Australian 2/9^th Battalion and one battery of the 4^th Royal Horse Artillery, the Australians attacked and captured Giarabub between 17 and 21 March 1941. The Australians left behind a salvage party and withdrew from the oasis on the following day, just before the Italo-German 'Sonnenblume' counter-offensive (24 March/9 April), which recaptured Cyrenaica.