To the pupils he teaches in Harrow schools, he's Mr Baird.

To followers of 1970s power poppers The Jags, he's the drummer. And to folk music fans of a certain vintage, he's the bloke who used to play the William Tell Overture on his head with Scots folk-rockers Contraband. Alex's Interlude, as this popular party piece became known, has been brought back into focus with the recent reissue of the one and only Contraband album. But as Alex Baird will tell you, it came at a cost.

"I did it for fun at the CD reissue launch party because it's on the album," says Baird, "but back in those days I had hair and you wouldn't notice the damage. This time, my head was covered in bruises the next day. So I wouldn't recommend it, especially to slap-heads like me."

Contraband was a group that seemed set for big things and its members delivered on that promise, although not under the Contraband name. Widely regarded as a Scottish Fairport Convention, they had much of what the Liege & Lief-era Fairport had to offer: a strong and very personable singer and frontwoman in Mae McKenna, jigs and reels delivered with an energetic backbeat and versions of traditional ballads that brought these venerable songs into the rock music arena. The loyalty they inspired was and is such that when the aforementioned album became available to license recently, one fan, Jim Phelan, started a record label, Celtic Folk, especially to re-release it.

In its original 1974 form the album Contraband achieved disappointing sales figures and its putative follow-up was shelved. In its aftermath, however, McKenna went on to success as a solo artist, as well as singing backing vocals for Kylie Minogue, Pete Townshend, Donna Summer and Scritti Politti. Brothers Billy and George Jackson, together with the band's fiddler, John Martin, created the standard-defining Scottish traditional group Ossian, with Martin going on to The Easy Club and the Tannahill Weavers. Guitarist Peter Cairney continues to work with his band Isla.

For Baird, the break-up of Contraband, although entirely amicable, was devastating. His life since then, though, has been nothing if not eventful.

"I'd never heard folk music when I met the band," he says. "I was a Cream and Who fan, and had been playing in a band called Stumble with a guy called Jim Ure while serving my apprenticeship as a fitter/mechanical engineer. Music was a hobby, nothing more, and I remember thinking when Jim announced he was leaving Stumble to go professional that he was off his head. He went on to do OK, though, and he's now much better known as Midge, so what do I know?"

Winning the Scottish heat of the then highly prestigious Melody Maker folk/rock competition took the band to London and brought them to the attention of Transatlantic Records, home to The Pentangle and myriad acoustic guitar pickers. Having just finished his apprenticeship and with something to fall back on, Baird jumped at the offer of a record deal that involved a rent-free flat for the band in Hendon, a modest weekly wage, a van, a PA and other equipment.

"There was no rock'n'roll lifestyle," he says. "We lived like a family, sitting down to dinner together, and we'd sing all the way to a gig and all the way back again. Maybe we were naive but it was great fun and there was never any bickering."

Years later, after Contraband split, Baird appeared on Top of The Pops (and The Old Grey Whistle Test) with The Jags, playing their Top 20 hit Back Of My Hand, and went on to tour the US and record their Evening Standards and No Tie Like A Present albums before the band imploded amid dodgy management deals and personal disagreements in 1982.

It was shortly after this that the mother of his girlfriend decided Baird could put his apprenticeship to use as a design technology teacher. Through a circuitous route, he arrived at the situation he now finds himself in, teaching drums in Harrow.

As for the (now retired) William Tell Overture routine, it was, says Baird, just something he found he could do.

"I remember on Contraband's first trip to London, for the Melody Maker competition final," he says, "we were all sleeping in the same room – Mae had the bed and us guys were all on the floor – and, when the light went out, I played the William Tell Overture on my head for a bit of fun. But the rest of them said, 'You've got to do that at gigs.' So I did. Then it went on the album and [seventies prog-rock group] Gryphon heard it and made me do it at their gigs too. But I can't do it now. I can't go into school looking like somebody's been using my head as a punchbag."

Contraband by Contraband is out now.