Great Britain 1988 £1-£5 "Castles" (1st Harrison printing), SG1410/3.
Superb unmounted mint, with full original gum, set of four in horizontal gutter pairs.
Following the issue of stamps for his wedding, the Duke of York was invited to design new stamps based for the first high value definitives of the Queen's reign. It was decided to use Castles as the theme.
The castles selected were Carrickfergus Castle in Northern Ireland, Caernarfon Castle in Wales, Edinburgh Castle in Scotland and Windsor Castle in England. The Duke of York visited each castle to take photographs, which were then used to produce the designs of the stamps.
The stamps were first printed in 1988 by Harrison and Sons. The De La Rue Giori presses were used to recess print the stamps. These presses were normally used in printing banknotes and it was the first time they were used to print stamps.
The Royal Mail was, however, concerned that the stamps could be easily forged with modern copier technology. As a result, a more secure version was issued in 1992, which included the Queen's head printed in an optically variable ink and elongated perforations along the vertical edges.