A wonderful bit of whimsy which included the observation that Helsinki just has to be a brilliant place to visit because it sounds "half helter skelter, half twinkly". "Or," countered the cynical co-pilot (played by Roger Allam of The Thick Of It fame), "like a sink of hell."

Podcast: John Finnemore interview

In a very special edition of the Rum Doings podcast, we are joined by comedy writer John Finnemore. We have discussed Mr Finnemore's work on Rum Doings in the past, especially the fantastic Radio 4 sitcom Cabin Pressure.

The Pressure of Perfectly Paced Plotting

BBC Radio 7 has been repeating Series 1 of Cabin Pressure - which I completely missed the first time round. It's lovely show with an admirably small number of characters, as the title suggests - pressured relationships in one cabin of one aeroplane.

Only on radio, where the listener brings the scenery, can a comedy about a small airline take off so successfully. (I'm a devoted fan of that ultra-camp TV show The High Life, but it only had one series.) This has the setting and characters from which classic sitcoms are built: a struggling business, a canny but inexperienced proprietor (Stephanie Cole), her wily chief pilot (Roger Allam), his ambitious young rival (Benedict Cumberbatch) and the good-hearted but daft son of the boss (John Finnemore, who's also the writer). It's really funny.

Welcome return for John Finnemore's situation comedy about a struggling small charter airline. It's blessed with a classy cast, Roger Allam, Benedict Cumberbatch, Stephanie Cole as Carolyn, the boss, and Finnemore himself as her perennially perky son Arthur. And today Alison Steadman arrives as Carolyn's sister. They haven't spoken for years. Arthur hasn't bothered to think about that as he's planned a cheery birthday trip for them all. To Helsinki. He's booked it on his Mum's credit card. And she thought it was proper business.

For the last six weeks, there has been one reason at least to put away the razor blade - a weekly appointment with Cabin Pressure, one of the funniest sitcoms ever to air on the radio.

It is always a puzzle to me as to why I sit through so much comedy with a 'We are not amused' expression when I find most of what goes on in real life belly-achingly diverting. Similarly, it is almost impossible to analyse the secret of good comic writing but John Finnemore's script for the six-parter had it in spadefuls.

So Finnemore, who has also written for Dead Ringers and Mitchell and Webb, had his characters with incompetence ranging against dry wit, and his landscape, that surreal world in the sky which is an airliner in transit. It could still have all gone wrong but his ear for a comic retort was equal to his instinct for a comical situation. The result was a six-week abdominal workout for listeners and, I hope, a recommission for Pozzitive Productions.

I gave the show a brief mention a few weeks ago, but now its run has finished, it's time to give Cabin Pressure its due. Its first episode was, I said, flawless. Nothing can be flawless for ever, but the writing and performances in this tight comedy have been exceptional. Let me put it like this: this is the only programme that has kept me close to a radio at 11.30 every Wednesday morning. Never mind Listen Again - you want to catch this as soon as you can.

The setting might be novel - a charter plane, with its skeleton crew of misfits - but the writing obeys pretty much all the necessary rules of classic British sitcom writing, which are simple. In fact, students of the art form would do well to listen to it and take notes. You need little more than an inverted class relationship, a sense of failure, an idiot, and a scary authority figure. What writer John Finnemore has done as well is to add, without tilting things off balance comedy-wise, some depth to the characters.

So the dragon of a boss, played by Stephanie Cole, is revealed to be scared of becoming a 'little old lady'; and the wonderfully supercilious Jeeves/Sergeant Wilson figure, the man who should be Captain but isn't (a perfect performance by Roger Allam), is shown to have weaknesses of his own. The show deserves an award.

The fourth edition of this five-star sitcom opens with what is now a running joke on how the budget airline crew either don't know or don't care about the technicalities of taking off, flying or landing.

I've listened every week, expecting it to crash land but John Finnemore's writing flies in first class. And then there's Roger Allam's performance as the bitter first officer who despises his captain. He is to sarcasm and sneering what Rowan Atkinson's Blackadder was to, well, sarcasm and sneering. Radio sitcom success stories are rare: let's hope this one's in from the long haul.

I can recommend an excellent new comedy from Radio 4: Cabin Pressure, about the trials and misfortunes of a budget airline. Well, not really an airline, as the company's supremo Carolyn explains to her hapless captain, for you cannot arrange one plane in a line. 'If anything, it's an airdot.' This show makes great use of both the misery of failure and the mystery of flying. (There is an excellent running joke about how no one really knows how planes stay in the air.) I cannot find a single flaw in it. So top marks.

Well-defined characters, strong casting and great writing do a good sitcom make. Sounds easy, but few get it right. I am, therefore, delighted to announce that this new series is so funny that I listened to it three times in a row, laughing more loudly each time at the lines I now knew were coming.

It's set in a small airline company staffed by two pilots and run by a forbidding 60-something woman who, one of her staff suggests, sharpens rather than brushes her teeth in the morning. Roger Allam's character is on a par with Basil Fawlty as the embittered pilot on his way down.