BEN MILLER is lying in a trench, trapped under a wooden beam, while a black metal bomb lies ominously beside him.

“I must be absolutely still,” he says, his voice earnest but trembling. Then he strikes a match. Nothing happens. He tries again, and again, and again. A voice shouts “cut” and the lights come up on a studio in the BBC’s TV Centre.

Welcome to the new series of The Armstrong And Miller Show. Far from being in mortal danger, Ben is filming a sketch in character as culture buff Dennis Lincoln-Park.

“He was inspired by Lord Clark’s Civilisation,” explains Ben later, still in costume, over lunch in his dressing room.

“He’s a real enthusiast about culture and he talks about some really exquisite item in great detail, he builds it up and then it always ends, ‘And of course, it is absolutely priceless’, at which point, he accidentally destroys it.”

Lincoln-Park is just one of a new bunch of characters the comedy duo will bring to life in their second series on BBC One.

But there are some familiar ones, too. “We’ve brought back the airmen and Frank Dad, you know the one with the bad curly hair, as well as the Flanders and Swann characters,” says Alexander Armstrong, tucking into his roast dinner in a polystyrene box.

“The drum I bang, every time we start writing a new series, is that we must try and keep it as fresh as possible and, if we have any old stuff in it, it’s really got to fight its corner and justify its place.”

So along with Lincoln-Park, we’ll also meet Jilted Jim, another of Ben’s characters, who decides to go on honeymoon after his wife runs off with their wedding DJ.

“He’s from somewhere in the Midlands and he says, ‘I’m a glass half- full kind of a guy, not alcohol though, I don’t like what it does to me’,” says Ben, in a Brummy accent.

“But he always ends up polishing off everyone’s drinks and switches to this really nasty person.”

Alexander adds: “We’ve also got a guy called The Reasonable Boss. He’s an MI5 boss, it’s sort of a Spooks scenario, but he’s absolutely adamant that his staff should never work a second over their allotted hour.

“They’re always on the brink of some massive breakthrough and they’re just about to find where the bomb has been left in the city . . .”

Ben picks up the thread: “It goes: ‘Sir, innocent people will die’. ‘It’s 5.31 Andrew, that’s not your responsibility’.” And the pair of them collapse in giggles.

You can tell they’re long-term friends. Cheshire-born Ben, 43, and Alexander, 39, or Xander, as Ben calls him, met at university in Cambridge, as members of the prestigious Footlights theatre group. They performed their first full-length show at the Edinburgh Fringe in 1994, which led to the sketch show Armstrong And Miller on Channel 4, from 1997 to 2001.

In 2007, the series was resurrected on BBC One, rebranded The Armstrong And Miller Show, and they haven’t looked back.

“We know better now what our strengths are,” says Alexander, on making the second series of their new show.

“There was a lot of talk before the last series about how we would transfer from a Channel 4 to a BBC One double act. The answer was simply remain doing things that make you laugh. Perhaps make your references slightly less obscure, but I think we’re much more comfortable now.

“We’ve found the BBC One audience and we have a better idea of what characters to work on.”