Walker was later conscripted into the armed forces and applied to volunteer for tanks, but was required to wait until a training place became available. In the meantime, Walker worked with the Dunlop Rubber Company, which offered 12 scholarships annually and was based at Fort Dunlop in Erdington, Birmingham. Walker had been evacuated to Erdington and lived with the Bellamy family at 58 Holly Lane. On 1 October 1942 he travelled to Wool in Dorset, where he reported to the 30th Primary Training Wing at Bovington, the headquarters of the Royal Armoured Corps.