RD: Characters such as Mrs Emery, an incontinent old lady, and Harvey, a grown man who is still breast-feeding, have led to accusations of bad taste.

Lucas: The accusations are right. Our defence is that the sketches are funny.

Walliams: We were criticised as if there is a list of things that can’t be portrayed in comedy. To me, that list doesn’t exist. I went to a hospice in Wales and there were a lot of young boys who were dying of a muscular wasting disease but were dressed as Andy. For them, life is comic and tragic and he’s someone they can relate to. They don’t get offended – other people do on their behalf.

RD: Do you worry that you’ll fall out of favour?

Walliams: This is the time people particularly want to come and see Little Britain live and buy the DVDs. In five years’ time, we accept that something else will have come along.

Lucas: The third series had more viewers than ever, but wasn’t well received by the critics, so I think people are looking for the next big thing already. I’m waiting for Catherine Tate’s next move. It’ll be good for someone else to experience what we have and it’ll give us a chance to do something different.

RD: In the past, you’ve found success both as a double act and individually. David, you recently swam the English Channel for Sport Relief. Do you have any other solo projects coming up?

Walliams: I’m in a new adventure film called Stardust, starring Robert De Niro and Michelle Pfeiffer. I play the ghost of a prince who burnt to death, so I appear in a singed nightshirt. Lucas: The BBC has filmed The Wind in the Willows for Christmas and I play Mr Toad. It’s a real thrill and not like anything I’ve done before. My mum’s friends have been telling her how nice it will be seeing me in something other than Little Britain, the inference being that this will be more respectable.

RD: You’ve recently signed a new three-year deal with the BBC, so what is the future for Little Britain?

Walliams: [We’ve done] a Christmas special, but there are no plans for another series at the moment.

Lucas: We’ll definitely do more with some of the characters – possibly a film. But the transition to the big screen is difficult. It’s better to make a good TV show than a bad film. At the end of the day, John Cleese is remembered for Fawlty Towers and Ricky Gervais for The Office, so you don’t need to make hit films to endure. There are waxworks of Lou and Andy in Madame Tussauds. We’ll know it’s the end when they melt them down. My model could probably be used for all three of the Beverley Sisters.