Seahorse high value stamps

Seahorse high value stamps are United Kingdom definitive postage stamps issued during the reign of King George V. First released in July and August 1913, these high-denomination stamps were prepared with the personal interest of the King, who was an avid philatelist. Produced using intaglio (recess) printing, the series served as the standard British high-value definitives throughout the interwar period until being replaced in 1939 by the King George VI high value series.

Over their period of issue, the stamps were manufactured under successive contracts by several different printing firms. The initial contract was held by Waterlow Bros & Layton, who produced the stamps in four denominations: 2/6 in brown, 5/- in red, 10/- in blue, and £1 in green. In December 1915, the contract transferred to De La Rue & Co, who increased the stamp height by one millimetre and discontinued the £1 value. Production was subsequently taken over by Bradbury, Wilkinson & Co. Ltd in December 1918, before reverting to Waterlow & Sons in 1934. In addition to domestic postal use, the stamps were issued with overprints for the Irish Free State and the Morocco Agencies.

The stamp design is distinguished by its dramatic central motif of Britannia standing on her chariot behind three writhing horses on a stormy sea. Bertram Mackennal, an Australian sculptor, modelled the profile head of King George V, adapting a portrait he had previously prepared for the Coronation medal. The surrounding lettering was designed by George W. Eve, and the printing dies were engraved by J.A.C. Harrison. On the initial printings, the background behind the King's head was rendered with horizontal engraved lines, which were altered to cross-hatched lines when Waterlow & Sons re-engraved the dies in 1934.

Printings are distinguished by stamp height, printer colour variations, and the shading behind the King's head, which features horizontal lines on issues prior to 1934 and cross-hatched lines on the re-engraved 1934 issue.