In 1976 commemorative stamps were issued to illustrate British cultural traditions, all closely linked to music and, as you can see, some musical instruments. They show a Welsh Archdruid, English Morris dancing, a Scots piper, and a Welsh harpist.
Later, in 1984, one of a set of stamps about the work of the British Council included this one. The others were on the subjects of medicine, construction and language.
This is a post for Sunday Stamps, now hosted by Violet Sky at "See it on a Postcard!"