Cathal Joseph Patrick Smyth, aka Chas Smash, singer, dancer, washboard and spoon player in Madness, is doing the washing up when we speak on the phone.

"I've just moved house so there's a lot to sort out," he says, partly drowned out up by the sound of a running tap.

One or the other of his three children, Casper, Milo and Elouise, wanders in with questions for dad throughout the interview. Not that domestic life is the only thing keeping him busy.

After Madness split up in 1986, Chas worked as an A&R man and set up his own label, although Madness never really went away.

A foot-stomping appearance in front of 70,000 fans at London's Finsbury Park in 1992 launched them back together, inspiring Our House, the West End's latest hit musical based on Madness songs.

"We came up with the concept in the pub a few years back," says Chas. "We got really excited and I went home to ask what the wife thought and she said 'you silly old b******, go and get yourself a proper job'."

Taking no heed of her advice, Chas and the rest of Madness went to see their publishers and writer Tim Firth best known for his TV show Preston Front.

Set in Camden, Our House is a story about a teenager who commits a petty crime to impress his girlfriend and is woven around Madness' greatest hits.

"I've got to keep a foot in the thespian camp, darling," says Chas.

By all accounts he'll be doing this for a while as the show has already been extended for several months into the summer, proving just how timeless Madness's appeal is.

"I could never have imagined my life would have taken this path," says Chas. "For the first few years, we thought it could end at any minute. It's incredible really. In fact, I'm writing a song about it. Do you want have a listen?"

At this point Chas starts to sing, unaware I can't quite make much out over the clatter of plates. Then there's a crash, the phone goes dead and Chas doesn't phone back. Perhaps he dropped the phone in the washing-up bowl.

The Madness concert has sold out.