There’s a fair bit of snobbery around when it comes to improvised comedy. Accusations range from it being somewhat inconsequential to overly smug, but there’s little doubt that when ad-libbing on stage hits the heights, there are fewer more joyful experiences for an audience. Paul Merton has long been one of the form’s key practitioners and he’s back on the road with his Impro Chums for more made-up mayhem.

‘It’s just doing what we all do as kids, playing endless, imaginative games,’ he states in defence of the craft. ‘Kids often unpack a Christmas present and end up playing with the box. Impro is like playtime, the bit of school you liked! If you spark each other off in improvisation, it creates a really good spirit. It’s the spirit of the playground.’

Paul and fellow grown-up nippers, Mike McShane, Lee Simpson, Richard Vranch and Suki Webster, are taking the show to an array of locations from Glasgow to Guildford and Inverness to the Isle of Man. For Merton, it’s all about keeping his comedy muscles flexed. ‘People ask me why I do the Comedy Store Players and the Impro Chums, and the answer is that it keeps me match-fit. If I go away on holiday for two weeks, when I come back I find that everyone else has sped up ten per cent. It takes me until the interval to catch up and jump on the bus. There is such a thrill in the notion of playing, say, a Bulgarian lion-tamer trying to explain in fractured Spanish that the yoghurt in the fridge has gone off. It’s a complete delight.’

While Merton made his theatrical acting debut last year in My Obsession, as a comedian who wakes to find in his hotel room a smitten fan (performed by the play’s author and Merton’s wife, Suki Webster), he knows that although a night of improv has its own difficulties, there is one distinct advantage to being in an unscripted work. ‘We don’t have to learn any lines. We can do it all off the top of our heads, and that’s an absolute joy. I’m sorry, Mr Sondheim!’

Paul Merton’s Impro Chums is on tour until Wed 17 Jun