The War Medal 1939–1945 was instituted by the United Kingdom on 16 August 1945 and was awarded to all full-time personnel of the armed forces and Merchant Navy for serving for 28 days, irrespective of where they were serving, between 3 September 1939 and 2 September 1945 inclusive, the full duration of the Second World War.

[1][2][3][4] The qualification requirement for the award of the War Medal 1939–1945 to full-time military personnel was 28 days of service, wherever rendered.

[3] Full-time paid members of the specially approved colonial and other military forces, militarised police or militarised civilian bodies which were eligible to qualify for campaign stars, were also eligible to qualify by 28 days of service during the qualifying period as laid down for the force concerned, as follows:[3] The qualification for the specially approved categories of uniformed civilians who were eligible to qualify for Campaign Stars was 28 days of service in the area of an army operational command overseas, or overseas from or outside the country of residence in non-operational areas subjected to enemy air attack or closely threatened.

Service in the United Kingdom or in the territory of residence, other than in an army operational area, was not a qualification for these categories.

Preston also designed the bronze memorial plaque which was presented to the next-of-kin of British servicemen and women who fell during the First World War.

The recipient's name was impressed on the rim of the medal awarded to Indians, South Africans and, after a campaign led by veteran organisations, by Australia.

In the case of Indians, the recipient's force number, rank, initials, surname and service arm or corps, and in the case of South Africans and Australians, the force number, initials and surname, were impressed on the rim in block capitals.