David Mitchell and Robert Webb think 'Peep Show' could go on forever.

The comic actors - who have portrayed flatmates Mark and Jeremy in the sitcom since 2003 - can't see the show ever running out of material and having to end.

Speaking to the new issue of Reader's Digest magazine - which is out now - David said: "Two once-young men, now not quite so young, are living together and facing the problems that everyone faces.

"There's pretty much a bottomless pit of potential problems that we can cover."

The pair believe the relationship between their characters work so well as they can "look down" on one another.

David said: "Mark and Jeremy make each other feel better because they have someone to look down on

"Mark thinks, 'My job is going badly, but not as badly as his', while Jeremy thinks, 'I haven't embraced the dream, but he has even less.'

"It's like people who drink and smoke and say, 'That bloke drinks and smokes more than me. I'll be all right as long as he's still alive.' "

Robert believes the pair are like a "married couple" and will always be together.

He said: "Jeremy and Mark are almost like a married couple. At one point, Jeremy considers ditching Mark for another friend. He thinks, I could be in the mainstream instead of stuck with Mark in our own little puddle. But Jeremy and Mark will always remain in their own little puddle.

"They both think that, the moment they open the door, the party stops and everyone goes 'Shhh!' We all go through that feeling of being an outsider."