Yes, Mr L - Brian 'Dolphin' Taylor. Not sure why Smudge didn't give more of an answer.
Actually, the story goes that he was auditioning for bassist. He got put on the skins and stayed there. playing for TRB (including on the brilliant 'Power In The Darkness' album), SLF (on the rather meh 'Now Then') and, later, Spear of Destiny (whose rhythm section was inexplicably named The Engine Room).
If anyone can remind me which track starts with Tom saying, 'Take it away, Dolphin', I'd be happy to hear. It's been bugging me, and all my TRB music is on cassette, which I can't play right now.