When the "Mobile Division (Egypt)" was formed after the Munich crisis in the autumn of 1938, it consisted of a Light Armoured Brigade, the old Cairo Cavalry Brigade, a Heavy Armoured Group and a Pivot Group. The heavy Armoured Group consisted of the 1st and 6th Royal Tank Regiments. In January 1940 Mobile Division (Egypt) was renamed 7th Armoured Division, the Light Armoured Brigade became 7th Armoured Brigade and the Heavy Armoured Group became 4th Armoured Brigade. Lt-Col. H. R. B. Watkins, who had been commanding the Heavy Armoured Group, was succeeded in command of 4th Armoured Brigade by Brigadier J. A. L. (Blood) Caunter, DSO, MC, who had commanded 1st Royal Tank Regiment from 1934 to 1939. The brigade was at the time in Main Barracks at Abbassia, having returned from the desert near Mersa Matruh at the end of November 1939, when it was clear that Italy was not at that time going to declare war against us.

Soon after its birth the organisation of the brigade changed: 1st Royal Tank Regiment went to 7th Armoured Brigade, 7th Hussars from 7th Armoured Brigade taking their place. At that time 6th Royal Tanks had about a dozen A 9 medium tanks, the forerunner of the Valentine : all the rest of the tanks of the brigade were light tanks, mostly Mark VI and Mark VI B. There were not enough two-pounder guns for all the A 9s nor enough machine guns, though most of the tanks managed to be equipped with at least two out of their full complement of three.

In February General Wilson held two large scale exercises, in the first of which the brigade took part. The A9s were brand new and had not been run in: there were no spares in the country. However HQ British Troops in Egypt insisted that they should take part in the exercise, with the result that almost every one seized up.

In April it became clear that the Italians were viewing warfare with a more favourable eye. 11th Hussars and the Support Group moved up to the area of Sidi Barrani and Mersa Matruh, followed in the second week of May by 4th Armoured Brigade, which concentrated just south of Gerawla. On the night of 10/11th June, when war against Italy was declared, 11th Hussars and the Support Group moved up to the frontier, 4th Armoured Brigade moved at first light on June 11th by the desert track known as the "Road to Rome" to the area later known as "Conference Cairn", on the top of the escarpment Southeast of Halfaya. 11th Hussars, supported by 4 RHA, had already captured Sidi Omar. The brigade's first action was the attack on Fort Capuzzo. The attack was preceded by naval and air bombardment and was a complete success: those tanks, which were lucky enough to have guns, bombarded the walls of the fort. By modern standards it was a primitive, almost mediaeval scene. It served one great purpose in that it gave every man in the brigade a hearty contempt for the enemy, and instilled a fear of our armoured forces into the Italian Army, from which they never recovered. The capture of Capuzzo was followed by a period of aggressive patrolling, of which the main burden was borne by 11th Hussars. At the end of June 7th Armoured Brigade relieved 4th Armoured Brigade, which then concentrated near Mersa Matruh. In the late summer it was joined there by the rest of the division, less the Support Group. It had become clear that the Italians, who had re-taken Capuzzo in July, were planning a further advance, and it had become essential to restrict the mileage of our antiquated tanks which were fast wearing out. In the middle of September the Italians advanced with great pomp and ceremony as far as Sidi Barrani, harried by the Support Group, RHA in particular causing them great annoyance. Having reached Sidi Barrani the Italians began to build perimeter camps in a ring from east of Sidi -Barrani at Meiktila, through the Tummars and Nibeiwa to Alam Rabia, the Sofafis and Halfway House to Halfaya itself.

While Jock columns of the Support Group harried these camps and prevented the Italians from closing the gap near Bir Enba between the camps at Nibeiwa and Adam Rabia, the brigade was getting stronger every day. More A9 and A10 cruisers were becoming available. 6th Royal Tanks now had two squadrons of cruisers and one of lights, and 7th Hussars had one cruiser and two light squadrons. In November 2nd Royal Tanks complete with A 13 cruisers, the forerunner of the Crusader, and 3rd Hussars complete with lights joined 7th Armoured Division, having been sent out in advance of the rest of 2nd Armoured Division. and Royal Tanks less one squadron with one squadron of 3rd Hussars under their command joined the brigade, a welcome addition. One battery of 1 RHA also came under command, the first gunners to become a permanent part of the brigade.

On December 8th the brigade moved forward from the Matruh-Siwa Road to the area of Piccadilly. Early on the following morning, while 4th Indian Division supported by 7th Royal Tanks with their Matildas attacked Nibeiwa camp, the brigade slipped through the gap on their left, which Support Group with RHA had done so much to keep open. With hardly a pause the brigade went straight through behind all the camps to cut the coast road west of Sidi Barrani, where it was firmly established by last light. By this bold move the large enemy forces in Nibeiwa, the Tummars, Meiktila and Sidi Barrani were completely cut off. The brigade stayed in that position roping in crowds of prisoners, while 4th Indian Division attacked and cleared in turn the camps to the east and 7th Armoured Brigade struck through to the west to Buq Buq, where it was almost engulfed in the crowds of prisoners. Leaving 6th Royal Tanks to help 4th Indian Division capture Sidi Barrani itself, the brigade then turned south again to Bir Enba and swept through the desert, chasing the Italians fleeing from Rabia, the Sofafis and Halfway House into Bardia itself. By-passing Sidi Omar and Sollum, the brigade went straight to cut the main road from Bardia to Tobruk a few miles west of the perimeter of Bardia defences. This swift, bold stroke produced strong reaction from the Regia Aeronautica, which made life very unpleasant, and also strained the Q resources almost to breaking point. Coy RASC drove day and night without stopping, collecting captured petrol from Sidi Barrani and delivering it to the much-bombed brigade B echelon, who were kept going by the tireless energy of the late Brigadier (then Major) George Webb.

Support Group, having captured Sollum, relieved the brigade west of Bardia. After coming back to the frontier to reduce the garrison of Sidi Omar, the brigade concentrated just west of Capuzzo, while 6th Australian Division came up to take Bardia. Christmas was celebrated here on half a pint of salty water a day and bully and biscuits.

The attack on Bardia began on December 27th: as soon as its success was sure, the brigade moved west along the Trigh Capuzzo to El Adem, where the pile of ruined aircraft bore witness to the effective work of Air Commodore Collishaw's gallant little Desert Air Force, and drove the enemy inside the perimeter defences of Tobruk, while 7th Armoured Brigade and Support Group completed its encirclement to the west.

As a result mainly of mechanical troubles and the complete lack of spares, it now became necessary to re-organise the brigade. 6th Royal Tanks were therefore dismounted, and, much to their chagrin, had to return to Alexandria, their tanks being handed over to the other two regiments. On January 22nd 6th Australian Division began the attack on Tobruk, 4 RHA taking part in the fire programme. The following day the brigade, taking 3rd Hussars also under command, advanced straight to Mechili, where the Italians' sole remaining mobile force was known to be. Owing to a combination of unfortunate circumstances, we failed to prevent their escape into the hilly country to the north. The only maps were extremely old and inaccurate Italian ones, the tanks were nearly empty of petrol and to make it worse a dust storm was raging when the brigade reached Mechili. While Derna was being captured by the Australians, a further pause ensued to allow the much harassed administrative services to catch up.

It now became clear that the Italians were intending to abandon Benghazi and evacuate Cyrenaica altogether. In spite of the great administrative risks involved, the division advanced south-west from Mechili on February 5th, the brigade leading. While the brigade was filling up at a dump formed 30 miles south-west of Mechili, news came that 208 (A/C) Squadron RAF had seen a great convoy moving south from Benghazi. A wheeled force was hurriedly formed consisting of 11th Hussars, 4 RHA, 2nd Battalion The Rifle Brigade and one battery of 106 Anti-Tank Regiment RHA. This preceded the brigade, heading straight for the coast road west of Msus. As soon as replenishment was complete, the brigade set off again, having to traverse fifteen miles of the worst stony ground ever experienced. The delay was exasperating: to make up for it the brigade carried on until the moon went down at one o'clock in the morning of February 6th, by which time the brigade was some ten miles east of Msus.

Petrol was again the deciding factor. A third line RA S C company full of petrol had been brought on from the dump without authority and had got lost during the hectic night march. By midday however petrol had been scraped up by robbing everyone else, and the brigade was able to start again, heading straight for Antelat, Sceleidima being held by the enemy. Late that night Colonel John Combe's wheeled force had cut the road, arriving two hours ahead of the Italians. Throughout February 7th the Rifle Brigade held the road while 4 RHA pounded away precious ammunition at the bewildered Italians. By the evening 4th Armoured Brigade, considerably depleted as a result of mechanical troubles, had reached the cross tracks near two water pumps known as Beda Fomm. On the morning of February 8th the Italians made one more futile attempt to break through the Rifle Brigade on the coast road, while the brigade, destroying a detachment of Italian tanks trying to outflank the Rifle Brigade on the east on its way, swung up to the road and raked with fire the mass of tanks, lorries and equipment of all descriptions trapped between 2 RB and 4 RHA in the south and 1 KRRC in the north. It was not long before all was over and the last remnants of Graziani's army surrendered.

Tens of thousands of prisoners had been taken in this lightning campaign and a whole army destroyed at the cost of very few casualties on our side. Mechanically however we were exhausted. The whole division could only muster twelve cruisers and forty light tanks fit for another hundred miles. Bedecked with flags the brigade returned triumphant to Cairo, which it reached on February 23rd 1941, leaving all its tanks behind. There it began to reequip slowly with tanks repaired in the base workshops, celebrating its victory with the Christmas fare which had never been able to catch it up.