What is a Penny Black stamp? Google Doodle celebrates landmark British design

From Roisin O'Connor, published at Fri May 01 2015

The world's first adhesive postage stamp used in a public postal system, the Penny Black, is being celebrated in a Google Doodle on its 175th anniversary.

Featuring a profile of Queen Victoria, the stamp was issued on 1 May 1840 for official use from 6 May that year.

The idea of an adhesive stamp to indicate pre-payment of postage was part of Sir Rowland Hill’s proposal in 1837 to reform the British postal system.

Hill was granted a two-year contact to run the new system after creating a design, finally deciding on an easily-recognisable profile of 15-year-old Princess Victoria, which he believed would be difficult to forge.

Penny Blacks can be highly collectable, with one set of four unused 1840 stamps available on the market for a whopping £140,000, while used versions can still sell for around £870.

Despite these prices, they are not know to collectors to be particularly rare. The total print run of Penny Blacks is believed to have reached 286,700 sheets, or a total of 68,808,000 stamps. The only known complete sheets are owned by the British Postal Museum.

The late author Terry Pratchett made several allusions to the beginning of the adhesive stamp in his Discworld novel Going Postal.