Commemorative stamps, postage stamps issued to honour or commemorate a place, event or person, have been released by the United Kingdom since 1924.
Postage stamps were first used in Great Britain on 6 May 1840, with the introduction of the world's first adhesive postage stamp, the Penny Black.
Up until 1924, all British stamps depicted only the portrait of the reigning monarch, with the exception of the 'High Value' stamps, the so-called "Sea Horses" design issued in 1913, which were twice the size of normal stamps with added pictorial design.
In 1924, the first 'Commemorative' stamp was issued for the British Empire Exhibition.
PHQ Cards, postcard sized reproductions of commemorative stamps, have also been issued to accompany every new set of stamps since the mid-seventies.