A large mint block of the Penny Black. The idea of an adhesive stamp to indicate pre-payment of postage was part of Sir Rowland Hill's 1837 proposals to reform the British postal system; it was normal then for the recipient to pay postage on delivery. A companion idea, which Hill disclosed on 13 February 1837 at a government enquiry, was that of a separate sheet that folded to form an enclosure or envelope for carrying letters.
A magnificent mint block of 12 Penny Blacks One of the crown jewels of Great Britain philately. 1840 Black The magnificent unused o.g. four margin, bottom marginal block of twelve lettered SD-TI with full deckle edge selvedge and sheet inscription.