In this age of round-the-clock music television, it is easy to forget how music on TV was once a precious commodity.

Back in the Seventies, while Top Of The Pops could be relied upon to offer up a weekly diet of chart hits, for artists not falling under the mainstream umbrella there was only one destination on British TV: The Old Grey Whistle Test.

Launched in 1971, the BBC2 late-night show gave an early visual platform to such legends as ...