This Sunday, the UKTV channel Gold will be screening a 30th-anniversary Fawlty Towers reunion documentary, featuring all of the main cast, including, uniquely for such an exercise, Connie Booth. Here lie revealed the inner workings of a show that exorcised John Cleese's comic demons while inspiring six hours of the tightest, most well-worked farce ever made for television. Brilliant but slightly exhausting – something that might also be said of Reggie Perrin – the disinterred and retooled David Nobbs sitcom whose origins are now also well over three decades old.
Next week, on the other hand, sees the return of a sitcom that is highly unlikely to be feted in 30 years' time, Flight of the Conchords. There is no sophisticated comic engineering à la Fawlty Towers here, or a high Reggie Perrin-style concept. In fact, Flight of the Conchords comes with minimum concept. Two New Zealanders try to make it as musicians in New York. That's it. Indeed, it's not even gut-bustingly funny. So why does it leave such a warm feeling in so many viewers?
"Formerly New Zealand's fourth most popular guitar-based digi-bongo a cappella-rap-funk comedy folk duo" (Wikipedia more helpfully categorises them as "sub pop"), Jemaine Clement and Bret McKenzie have been stealthily conquering the world. Flight of the Conchords' first incarnation was on Radio 2 in 2004, after the duo's Perrier nomination at the previous year's Edinburgh Festival. Rob Brydon narrated, and Jimmy Carr played their number-one fan, Kipper.
And now they've broken into both television and the States. This, the second season of their HBO show (showing on BBC4 here), is to be followed by a tour of North America. Commentators in the US professed themselves baffled as to why HBO added the show to their esteemed roster, but were won over nonetheless. That seems to be the way with this pair of comedians whose songs wryly catalogue their mishaps and shortcomings. Not a lot happens. There are no intricately worked plots or earth-stopping punchlines.
But then quite often in sitcoms, it seems, less is more. From Tony Hancock to Larry David, a light grip on the "situation" side of the sitcom equation can often intensify the comedy. It can be so much more relaxing as well, none of that awful gag-driven needling of studio audiences that so often sounds like people being harried with cattle prods.
In fact, one of my favourite old sitcoms starred Hywel Bennett as the eponymous Shelley, a slacker before the term was coined. Shelley's inaction, like Hancock's before him, allowed room for comic rumination. Being instead of doing. For this sort of comedy, you need the right deadpan face. Hywel Bennett had it, Hancock had it and Jemaine Clement has it. He looks a bit like Mick Jagger if Jagger had experienced repeated rejection instead of uninterrupted success.
Of course, the extra dimension to Flight of the Conchords is the songs – often wistful ditties that comment on the action and whose titles I defy you not to smile at. Songs like "The Most Beautiful Girl (In the Room)" are exceptions to the rule that the comedy pop song is a contradiction in terms. Flight of the Conchords is back, and it's time once again to look on the bright side. Only don't expect to be able explain exactly why.
'Flight of the Conchords' begins on 12 May at 10.30pm on BBC4