The 'unsung' work women undertook during the Second World War is being recognised in a new series of Royal Mail stamps.

Fourteen black and white photographs showcasing the new roles women adopted during the war years will go on sale next month.

Among them is a rare picture showing female codebreakers working at Bletchley Park.

Royal Mail says the new stamps pay tribute to the 'vital contribution' women made to the war effort in a huge variety of ways between 1939 and 1945.

There are 10 stamps in the main collection while a further four stamps are presented in a miniature sheet and showcase the brave work of the ferry pilots of the Air Transport Auxiliary – known as the ‘Spitfire Women’ – who were a ground-breaking group of female pilots.

Until 1941 women's work was mainly voluntary but the increased demands of a world at war meant that female conscription because necessary and by the middle of 1943 women were in wartime employment working in industry, agriculture and women's services.

The women’s auxiliary services were established at the outset of the war: the Auxiliary Territorial Service (ATS) in 1938, and the Women’s Auxiliary Air Force (WAAF) and Women’s Royal Naval Service (WRNS) in 1939.

To begin with, roles in the ATS were limited to cooks, cleaners, orderlies, store-women, and drivers, but as the war went on these were expanded to include other duties, notably work on the anti-aircraft sites.

Among the volunteers were many women from the then British colonies and Dominions, who served in the auxiliary and medical services. Other women worked as nurses, air raid wardens and tube and bus drivers, while over one million women volunteered with the Women’s Voluntary Services.

Come the end of the war many of these roles disappeared, but women’s contribution to the war effort is commemorated by the Women of World War II memorial in central London.

David Gold, Director External Affairs & Policy, Royal Mail, said: "These stamps are a tribute to the millions of women who contributed to the war effort and the Allied victory. Their bravery and sacrifice is often overlooked, but their work helped to drive some of the post-war social changes that eventually saw equal opportunities and equal pay legislation.

"We must also remember the women who supported the war effort at home, managing households despite the unceasing demands of total war."

Royal Mail says it has worked with university and museum experts to design the new collection.

The collection called Unsung Heroes: Women of World War II go one sale from May 5 for £16 but can be pre-ordered now here or by calling 03457 641 641.