"We're supposed to be intelligent people, not the London School of Economics!"

The first episode of a TV series is incredibly difficult to get right, because it has to do everything. You’ve got to introduce your characters, their environment, their relationships, and the rest of the set-up for the next six/twelve/twenty episodes, while juggling a self-contained plot for that one episode which has to come to a satisfactory conclusion by the end, that conclusion summing up, if you’re doing it right, the series as a whole. A sitcom’s harder than a drama, as you’ve only got half an hour, and on top of all that you’ve got to cram in some decent gags.

With all this to do, it's small wonder few sitcoms manage to launch with a satisfactory bang, but Ever Decreasing Circles is a towering exception. Writers John Esmonde and Bob Larbey hardly make things easy for themselves with the concept they have to introduce - humourless community busybody Martin Brice (Richard Briers) and his long-suffering wife Ann (Penelope WIlton) have their already crabby marriage shaken up by the arrival of suave, relaxed hairdresser Paul Ryman (Peter Egan), who possesses every redeeming feature Martin does have, from a sense of humour through to modesty. Not exactly 'fat bloke left in charge of bakery' in set-up terms, but they lay it out and sew it up in twenty-five-odd minutes without breaking into a sweat.

The performances are of course great, but it's not only Briers' one-man tornado of pointless energy that makes it. Penelope Wilton runs the gamut of Play for Today kitchen sink emotions from frustration to anger, while leaving just the occasional chink of warmth, enough to stop the viewer wondering why she didn't just pack her bags years ago. Very much in their own world are Howard and Hilda Hughes, not quite the cardboard comedy suburbanites they initially seem, but certainly full of the spaced-out detachment of people who write letters to Points of View - Stanley Lebor's Howard, in particular, talks as if he's reading out each 'frank exchange' from a previously approved crib sheet.

In the middle of all this, Peter Egan just has to act normal - easier said than done in such a madhouse. But he's not completely immune to the mania. His first encounter with Martin leaves him bemused at the torrent of unsolicited advice about British Telecom ("and the same applies to the gas people, but more about them anon!") Five minutes in, he finds himself starting to mimic Martin's OCD ticks, counting the number of steps in the hall stairway along with Ann. The freakish set-up is laced with subtle touches like this. It would be going to far to say the viewer can empathise with every character, but they're all certainly recognisable as real people, which is more than can be said for a lot of more celebrated 'realist' comedies.

Circles (well,why not?) is fairly well celebrated these days, but too often in conjunction with that dread comedy adjective, 'dark', often by punters who seem to have got their sense of humour by copying it off the boy sitting next to them in the exam room. What's really at the centre of it is a monumentally insecure, self-centered man who can't see how he drags down everyone he touches. Where Esmonde and Larbey really impress is in gradually making what starts out as a grotesque monster, cranking the duplicating machine in a maniacal frenzy, into a sympathetic, tragic figure. It's there in the first episode, in Martin's inability (or refusal) to share everyone else's jokes, and the lonely image of his one-man all-night vigil camped in front of a troublesome articulated lorry with a knackered portable telly for company.

It's something the writers have specialised in. There might not be much of it about in Brush Strokes beside the odd maudlin barside chat with Elmo, but it's there in spades in The Other One, a sitcom with Briers as a desperate bullshitter bluffing his way through a skirt-chasing package holiday - a theme made famous by John Sullivan with his medallion-toting Kirk St Moritz in Dear John (another 'before-its-time dark masterpiece' of course).

It's even there in The Good Life - both Margot and Tom are guilty of burying themselves in their own busy little worlds while real life goes on elsewhere. It's really the theme of all comedy, dark or light, noughties or forties, Avalon-approved or ENSA-affiliated - the man for whom the world's just that tiny bit too much. Or as Martin puts it in one of his stilted attempts at self expression: "I wish people wouldn't take me literally. I just mean... things."