Rick Wakeman played keyboards with the Strawbs before making it big.

Davey Johnson played banjo and guitar with Noel Murphy before joining Elton John's band.

Long John Baldry was once in a group with Redd Sullivan.

David Jones used to play in South London Folk Clubs before changing his surname to Bowie.

Billy Connelly and Gerry Rafferty were the Humblebums before they became really famous.

Dave Swarbrick first came to attention in the Ian Campbell Group.

Linda Thompson (of Richard & Linda) was Callan's girlfriend in the 60s TV series and was in a duo with Paul McNeill before she met Richard.

On the subject of Jazz musos, Acker Bilk's brother, David, ran a successful folk agency in the late 60s, fronting such artists as Jeremy Taylor, Noel Murphy, Colin Scot and Derek Brimstone.