The stars of Peep Show, Channel 4's consistently brilliant and enduring sitcom about a pair of loser thirtysomethings wasting their lives in a permanent state of arrested development in a dreary flat in Croydon, have surely never looked so elegant and sophisticated.
Dressed today in smart suits, they are sitting on ornate armchairs in the splendiferous drawing room at a grand stately home on the outskirts of Reading. You almost expect to see a photographer dashing about taking pictures for a glossy magazine feature headlined: "Mitchell and Webb show us round their beautiful home."
It's not really their home, of course. We are on the British Embassy set of their latest venture, Ambassadors, and as you can see, this time the performers have left the Croydon flat far behind.
Written by James Wood (Rev) and Rupert Walters (Spooks), BBC2's promising three-part comedy drama zooms in on Keith Davis (Mitchell) and Neil Tilly (Webb), who are respectively the ambassador and his deputy at the British Embassy in the fictional central Asian country of Tazbekistan.
Keith and Neil have to deal with such inconveniences as a high-maintenance minor-royal-cum-trade-envoy. All the while, they are arguing over the competing demands of commerce and human rights in this oil-rich, not-really-very-democratic-at- all nation.
In the first episode of the series, which is shot in Turkey and the home counties, Keith and Neil have a huge stand-up row over whether they should petition the tyrannical president of Tazbekistan about a £2 billion helicopter contract or about the release of a British human rights activist. It's international geopolitics – with added laughs.
Reclining in their armchairs, Mitchell and Webb possess a natural ease with each other that stems from a friendship dating back to their first meeting at an audition for a Cambridge Footlights production of Cinderella 20 years ago. They banter and take the rise out of each other in the way that only truly close friends can.
They begin by expressing their delight that such a rich subject has never been covered by a British comedy drama before. Mitchell, 39, who is married to broadcaster Victoria Coren, observes that, "I'm very surprised that there haven't been about eight different series set in embassies, ranging from a big studio sitcom with lots of laughs to a very serious drama and everything in between."
"We're going to try every genre in this series," chips in 41-year-old Webb, in characteristic fashion. "Episode one is a sitcom, episode two is a serious drama, and it all ends in parody."
Picking up the baton, Mitchell continues, "It hasn't been done before because people previously thought, 'It hasn't been done before.' They said to themselves, 'That's spooky.' We're the only ones who thought, 'Sod it. We're going to build a house on that old Native American graveyard. I'm not superstitious. What could possibly go wrong?'"
In the same way, Webb chimes in, "There has never been a great British sitcom about a band. That's funny when you consider that among the community of comedians there is a large minority who would rather be pop stars."
Mitchell takes up the theme. "I would genuinely rather be a comedian than a pop star. I resent sharing my profession with so many failed rock stars, with people whose faces are too bent and whose musicality is too unoriginal to make it in the pop world. Just imagine, a touch more weirdness from Mick Jagger and he'd have been in On the Buses."
The pair's easy-going chemistry translates seamlessly to the screen. It has served Mitchell and Webb exceedingly well over the past 10 years on Peep Show, which is now the longest-running British sitcom on Channel 4.
However, it would be wrong to think of Ambassadors as "Peep Show: the Foreign Office Years". Webb, who is married to fellow performer Abigail Burdess and has two young daughters, comments that, "Unlike Mark and Jeremy from Peep Show, Keith and Neil are fully functioning human beings. They are ordinary people doing an extraordinary job.
"The characters in Ambassadors are happy where they are. They don't feel trapped – they're not like Basil Fawlty desperate for his hotel to be grander or Captain Mainwaring wanting to be a general."
Mitchell, who with Webb is preparing to film what looks set to be the last ever series of Peep Show, adds that, "It is inevitable that viewers will bring baggage from Peep Show, but this is a very different beast. It's less populated by characters who are incompetent, for a start.
"It's going to be very difficult to mistake Ambassadors for a sitcom set in urban Croydon – although I'm sure some people will still try. Perhaps to make it absolutely safe, Ambassadors should have been set in the Iron Age or Ancient Rome."
Referring to one of the most popular characters in Peep Show, Mitchell carries on that, "I can assure you that Super Hans is not going to appear in Ambassadors as a trade representative. That would be like turning Peep Show into a sort of Carry On franchise. This week they're running the Embassy, and next week they're working in a condom factory. Actually, that's not a bad idea. Is it too late for a quick rewrite?"
Now, Webb has gone back to the theatre, appearing at the Hampstead Theatre in Raving, a new comedy about the trials of marriage and parenthood.
Mitchell, too, is considering a return to the stage. When I ask if he would fancy one of Shakespeare's great comic roles, he jokes, "No, I want to do something older than that. I'm not comfortable with all that up-to-date Shakespearean dialogue. I'm going to do some untranslated Mystery play in Old Norse. I want to make sure we pack 'em in!"
Finally, there is one unresolved mystery in Ambassadors. Mitchell reveals that, "Keith's predecessor has left under a dark cloud. He just disappeared, and no one knows what has happened to him. Perhaps if they commission another series, it will eventually be explained."
Quick as a flash, Webb jumps in: "Maybe we could make a prequel starring Mick Jagger as the previous Ambassador."
'Ambassadors' begins on Wednesday at 9pm on BBC2