In 1981 the Post Office issues a set of stamps to illustrate various areas protected by the National Trust and one of them showed the Giant's Causeway in Northern Ireland. Above is the PHQ stamp card issued at the same time.
While I was looking for the card, I came across a National Trust book of stamps issued in 1995 and wondered if the Giant's Causeway had figured again. It hadn't but while I was on that line of thought I came across a Northern Ireland book of stamps.
Inside I was really surprised to find that inside the front and back covers were two postcards and the first had a stamp almost exactly the same as the 1981 design, only now it's 35p. Inflation!
The stamp is printed directly on to the postcard so I'm not at all sure whether it was a valid stamp. It looks as though it has phosphor lines on it, so maybe.
This is a post for Sunday Stamps, now hosted by Violet Sky at "See it on a Postcard!"