Something’s not quite right. I’m talking to one of the hardest men in rock: a bear of a bloke who has been banned from entire countries. And he is utterly charming.

Instead of being ferocious, Jean-Jacques Burnel is erudite, amusing and interesting. “Last year was our busiest for 30 years,” says The Stranglers’ strapping bass player and black-belt sixth dan karate master. “The gigs were well-reviewed as well as the album [the acclaimed Giants] and suddenly we’ve had offers from all over the world.

“I am proud of The Stranglers’ eclecticism and creativeness. We have proved all our detractors wrong.”

My reasons for being nervous are well founded. After all, JJ has form. He once kidnapped a journalist who had displeased him, and gaffer-taped one French writer to a girder at the top of the Eiffel Tower — without his trousers. Then there was the time he and his band were jailed in France for allegedly inciting a riot, their arrest in Australia for swearing on primetime TV, or the night they were escorted out of Sweden under armed guard at 2am. Heck, he once pushed original frontman Hugh Cornwell through a wall for annoying him. But today the 61 year-old is in reflective mood.

“Bans go with the territory,” he says cheerfully. “But I have been un-banned from countries too. I don’t particularly miss the trouble though. I invested heavily in aggro but now I’m more interested in taking out dividends. It’s been years since I was confronted by an angry mob!”

JJ is at home, close to the river in Chiswick, west London, before heading out with drummer Jet Black, keys man Dave Greenfield and lead singer Baz Warne, on what some have predicted could be The Stranglers’ last tour.

Last year, 74-year-old Jet was rushed to Oxford’s John Radcliffe Hospital after suffering breathing problems before a show at the O2 Academy. A member of the band’s crew, Ian Barnard, stepped in and filled his place. But while concerns remain over Jet’s health, JJ is upbeat.

“I thought that might have been the final tour,” he says. “It happened early in the tour, and that was it. He was out of commission for the rest of the year. We were in Istanbul in front of 15,000 hip young Turks singing our lyrics, and he wasn’t part of it. It seems strange. He is still with us at the moment, though, and we’ll see what he can do.”

Considering their legendary propensity for rock and roll excess, this band, who over almost 40 years have racked up 23 top 40 singles and 17 top 40 albums, are doing pretty well. Jet was once nicknamed The Hoover, after all. “I wonder what that alludes to,” says JJ, mischievously, joking that it must have been because of his fondness for housework.

“I don’t know if we partied harder than other bands,” he adds. “We didn’t compare notes. We may have partied quite a bit and fought quite a bit. But others have died.

“As you get older you lose friends by the wayside, though. It’s a normal process but it doesn’t make it easier.”

Yet still he remains the band’s hard man, and refuses to take any nonsense. When a fan at a show in Liverpool last year was foolish enough to throw a pint of beer over him on stage, JJ handled the situation with panache: maintaining eye contact, finishing the song, then going into the crowd to give him a slap. Not a punch; a slap. “There’s nothing more humiliating than being slapped,” he says, “especially by a bloke. It looks much better if you do things for yourself, rather than hiding behind a big gorilla.”

The band have been no strangers to trouble. At one point they were banned by the Greater London Council from playing anywhere in the capital — and then there was that incident in Sweden which saw them locked in an underground dressing room while their road crew were beaten up and their equipment smashed by rockers. They escaped by making Molotov cocktails and blowing up their cars.

“They were Swedish Teddy Boys,” says JJ. “They saw this band from London with a reputation and thought ‘let’s see how tough they really are’.

“It was like that everywhere we went. We became a scapegoat and we got attacked. Every night there were bottles and punch-ups and our van would get smashed up. We often had to lock ourselves in our dressing room because people wanted to lynch us. It was tedious but it became a habit. It didn’t faze us, but others freaked out.”

The attitude may be pure punk, but their music, with its catchy melodies, great lyrics, deep basslines and keyboard runs, has always been more than that. Songs such as Peaches, No More Heroes, Something Better Change, Always the Sun and the classic Golden Brown bear little resemblance to the three-chord bursts of noise spewed forth by their contemporaries.

“We’ve never considered ourselves ‘just’ a punk band,” he says. “We have a lot of punk ethics, though, and that was our apprenticeship. After that, you had all the shoe-gazers, and people who didn’t know how to face an audience or avoid bottles being thrown at them. But we did suffer early on for playing synthesizers.”

As well as a full-time job as one of the toughest men in rock, JJ still finds time to teach karate. “There’s no contradiction,” he says. “My students know what I do in my other life and know I’m dedicated and serious.”

So how did he get into it? “It was a fashion at the time,” he says. “Guys like Bruce Lee made martial arts look good, and I got the bug, and it has stayed with me ever since. It has also saved my arse a few times and kept me grounded.”

It also keeps him physically fit. “Everything you do in martial arts negates the ageing process,” he says. “I’ve never heard of a martial artist getting Alzheimer’s. I am building synapses all the time.”

And so to the big question: how much longer will they continue? JJ laughs. “Somehow we’ve managed to survive all this time, which is well past our sell-by dates. After 40 years we are still playing and thoroughly enjoying ourselves. But you can’t play this kind of music on a Zimmer frame, and Jet’s condition is reminding us of our finiteness.

“I know we have got fewer years in front of us than behind us... so let’s go and have some fun!”

The Stranglers

O2 Academy, Oxford

Monday, 8.15pm

Tickets: £23