Black Lace (of later "Agadoo" fame) performing "Mary Ann", the UK entry at the 1979 Eurovision Song Contest.
Glam-rock Eurovision style! A nice, if a bit too gimmicky, song and performance which helped the British return to the top-10 of the ranking after just missing out the year before - in fact, it looked like they would be among the main contenders at the start of the voting, although they were subsequently pushed down to 7th place.