PAUL ASKEW and NICK BOOTH talk shirts, trousers and ‘mucking about’ with saxophone player Roger Ruskin Spear, ahead of a major London gig with his band Three Bonzos and a Piano.

Sitting in a Kingston basement workshop surrounded by old radios, tailors’ dummies, 1940s microphones and dismantled trombones seems, somehow, the most appropriate place to meet Roger Ruskin Spear.

The “mad professor”of those 1960s loons the Bonzo Dog Doo Dah Band, Spear was responsible for much of the band’s visual on-stage madness – an act featuring exploding robots, smoking trouser presses, the infamous “rowmonium” – a machine designed to make a right old racket – and “the leg” – a mannequin’s leg which emits high-pitched theramin-like noises according to the position of one’s hand.

“Ahh yes, the shirt and trouser obsession,” explains Spear. “I saw a lecture by Gustav Metzger who was into something called auto destructive art. So that was my propensity for blowing everything up with the Bonzos. And it came from Duchamp really. We were into words. Things like shopping bags, shirts, trousers. All those sort of words came up as something you could use as an artistic expression.

“So I became obsessed with ‘how can I work shirt into something here’? So we were having long conversations about trousers and things like that. Then I found a trouser press in the attic of the house I moved in to. So that became an instrument immediately.”

Spear’s inventions, coupled with the songwriting talents of pianist Neil Innes and the brilliance of the band’s effete frontman Vivian Stanshall – who died in a fire at his Muswell Hill flat in 1995 – led to a Bonzos’ stage act that was once described by a critic of the time as “a ballet for the vulgar” and featured songs with titles like Jazz Delicious Hot Disgusting Cold.

“I thought up the title,” explains Spear. “I was sat at a Northern cabaret club at the bar, looking at these signs which said ‘get the pies, delicious hot’. And I just said to Viv: ‘That should be delicious hot, disgusting cold.’”

The track sums up much of the early Bonzos’ madness – band members swapping instruments resulting in a fantastic cacophony of trumpets, tubas, drums and assorted banging and clattering.

“It was designed as a non-rehearsed number, after the frustrations of trying to get the song Jollity Farm right. We were sort-of musicians. But to try to get Sam [Spoons, the drummer] to do the same thing twice, or in time… It’s the same with Three Bonzos and a Piano. That’s half our stage act – Sam getting it wrong,” he laughs.

Following the band’s split in 1970, Spear toured for 15 years with his solo show – the Giant Kinetic Wardrobe – but the years of loud explosions, robots and fireworks took their toll on his ears and left him with tinnitus. “I went to the hospital and they said ‘hard luck’ basically.”

The band reformed in 2006 for a joyous 40th anniversary show at London’s Astoria and a subsequent tour and new album. When that eventually ran its course (“there were tensions”) Spear, together with Spoons, sax player Rodney Slater and pianist Dave Glasson, decided to continue as the bite-sized Three Bonzos and a Piano.

On the group’s new album Hair of the Dog, Spear revisits his favourite obsession in the song Shirts 2010 – which features a vox pop recorded outside Kingston’s Sainsbury’s store to get shoppers’ opinions on said garment.

“I made the mistake of interviewing them on the way in. So I’d done all the interviews, packed all my stuff away, walked in to do my shopping. And of course all the people I’d interviewed were also shopping in Sainsbury’s. And they’re thinking ‘you’ve just interviewed me about shirts’,” he laughs.

Three Bonzos and a Piano play the Bloomsbury Theatre, London on Saturday, February 6. For more information, and to get hold of the new album, visit threebonzosandapiano.co.uk