Ben says they “never fall out” but that it’s a good sign if they both want the same character.

“You’re excited for the show if it happens, you think we must have really good material if we both want these parts.

“There are some things that are so obviously written for Xander and we’ve been doing it for so long now, we’re on the same team, you know?”

During their hiatus from being a double act, the duo branched out and took on their own solo projects.

Earlier this year, Ben starred in ITV’s Moving Wallpaper and Primeval, and he’s just directed his first film, while Alexander is a regular host on Have I Got News For You, starred in last year’s BBC One sitcom, Mutual Friends, and had his own BBC Two quiz show, Pointless, this summer.

Both believe this has actually helped them improve as a double act. “Every double act kind of manages that in their own way,” says Ben. “Morecambe and Wise never did anything apart, the two Ronnies always did plenty apart and we’re in the second camp.

“When we worked with each other exclusively, I think it made us a bit insecure, because you don’t know whether you’d be able to survive on your own, but we’ve both grown in confidence since we started working with other people.”

Alexander admits: “I think there was always an undercurrent of dread with the pair of us that our careers were hinging on Armstrong and Miller and nothing else.

“When we’d outlived our usefulness on Channel 4, and been put out to pasture, what the hell were we going to do then? We thought at the time that our futures had by definition to be very tightly wrapped up in each other, and I think that put an awful lot of pressure on us.

“Was it Truman Capote or someone who said when a friend of yours succeeds, a little bit of you dies. In the case of Ben and me, when each of us has succeeded, it’s actually meant a bit more liberty for the other one.

“We’re not responsible for each other, and I think our working relationship now is all the better for it – we just don’t row like we used to. It’s healthy, I think.”

Outside of work, they see each other socially and their children even share the same nanny.

“There’s about six months between our eldest son, Rex, and Sonny, Ben’s eldest, so Rex has a nanny in the mornings and Sonny has our nanny in the afternoons – it’s very incestuous, but it works really well,” jokes Alexander.

Over to Ben: “We’re not joined at the hip, but I really enjoy Xander’s company, I feel very lucky to be able to work with one of my best mates.”

Alexander adds: “We can dement each other, in the way that brothers do, but it’s very short-lived. It’s a brothers’ relationship really when you know someone that well.”

THE Armstrong And Miller Show returns to BBC One tonight.