I like comedies, I like dramas. Comedy-dramas I've never been sure about and Dirk Gently has all but convinced me they don't work. The eponymous hero is a detective who believes in "the fundamental interconnectedness of all things" but after this outing, even he'd struggle to make a case for that hyphen straddling the two genres.

Gently is the creation of Douglas Adams who was working on another of his cases when he died. This one began with a missing cat and ended with what seemed like the attempted murder of the three attractive leads, Stephen Mangan as Gently, Helen Baxendale and Darren Boyd, who was in the recent Whites with Alan Davies and seems to be cornering the market in sidekicks to curly-headed fools. They all survived but surely the show won't.

The soundtrack twanged with Randall & Hopkirk-esque harpsichord (or did that pair use a spinet?).

The hero chugged around in a Leyland Princess. But Dirk Gently lacked drama, despite blowing all of BBC4's special-effects budget for 2011 on a warehouse explosion, and it lacked comedy with not one halfway funny line - this only making me yearn for the return of Mangan's cFree Agents from last year and scour Amazon for a cheap box-set of Baxendale's Cardiac Arrest, deadly certain laughs of the darkest hue.

There was something satisfyingly leisurely about Dirk Gently, adapted from a Douglas Adams novel about an old lady's missing cat, and starring Stephen Mangan as the one-man "holistic detective agency" hired to find it. It wasn't the smoothest of narratives. I could never wholly applaud a plot that so late in the day relied on hypnosis and time travel (the only sci-fi trace element from the original story). And, although there was laughter and invention, I'm not sure that bumping into a closed door aspires to the heights of modern comedy, even when accompanied by the ditsy loose-limbed rhythms of 1950s jazz. But it had a pleasing, meandering pace to it. You had to admire the way that Dirk's investigative method - based on "the fundamental interconnectedness of all things" - made an unlikely virtue of stringing together unlikely coincidences. And Mangan did a fine job as the eponymous oddball loafer-genius, with his boffiny corkscrew hair, love of biscuits and the rapid eye movements of a man accustomed to making a quick buck and a quicker exit; Darren Boyd was good, too, as the bewildered but biddable sidekick Macduff. As the girlfriend, Helen Baxendale was as nice as ever. It wasn't Sherlock, but I wouldn't mind seeing what a series could do.

I have no idea how loyal the makers of BBC4's Dirk Gently were to Douglas Adams's Dirk Gently's Holistic Detective Agency, though I'd hazard a guess that a few liberties have been taken. The iPhones and Blackberrys were one giveaway; the various references to East 17 another. And, of course, the book's title has been truncated. Does it matter? Probably, to some of Adams's more devoted fans. In the context of last night's viewing, though, I'm inclined to think that for most of us it doesn't. Not a jot. Gently was so jolly, so rollickingly good natured, that to complain over such trivialities seems terribly poor form.

Gently is a detective. More than that: he is a holistic detective. He believes that everything is interconnected. And so when, on being hired to investigate the disappearance of an old lady's cat, he ran into an old friend from university, he was certain it was a clue. In a way, it was. The pair teamed up, tackling the triple mystery of Henry the cat's whereabouts, the departure of a businessman from a nearby warehouse, and the failing love life of MacDuff (the friend). What followed was a cartoonish series of escapades that saw Dirk prove his creativity, if not sleuthing skills, with his Scooby Doo-esque plans. He faked suicide to steal a set of psychiatric records, he hypnotised MacDuff to take him back in time (not literally, though there is some of that) and he pretended to be a patient at the practice of MacDuff's girlfriend. He found Henry, sort of - and a lot more besides. That nice old lady who hired him, for instance? Not quite as nice as she seemed.

Stephen Mangan - hitherto best known as Guy Secretan from Green Wing - was ideal casting as the hapless Dirk, and Darren Boyd just as perfect as MacDuff. Helen Baxendale, too, made a welcome return as MacDuff's disgruntled girlfriend. In fact, there wasn't very much you could fault about the production at all. Right down to the quirky camerawork and youthful, poppy soundtrack (who would have thought the Hoosiers could be so right in any situation?), the director, Damon Thomas, got it pretty spot-on. The result was a pleasingly festive-feeling adventure; part Wallace & Gromit, part Doctor Who, part The Secret Seven. And the best thing? There wasn't a Christmas tree in sight. Douglas Adams once claimed that Gently would make a better film character than his more famous hero, Arthur Dent. Based on last night's experience, he may well have been right.

Douglas Adams's fictional detective has already been portrayed on Radio 4 in Dirk Gently's Holistic Detective Agency and now in an adaptation by Howard Overman makes an amusingly inventive, if small-scale, transition to TV. Stephen Mangan plays the shambling, penniless sleuth who believes in the "fundamental interconnectedness of things" and possesses an unerring knack of stumbling to the right conclusion. In tonight's case, he is exercised by a lost cat, a missing inventor and an exploding warehouse. Events bring him into contact with two former university friends, the gullible MacDuff (Darren Boyd) and his girlfriend Susan (Helen Baxendale).

Douglas Adams always believed that Dirk Gently's Holistic Detective Agency would make a better film than his more celebrated novel, The Hitchhiker's Guide to the Galaxy - although we can only wonder if the hugely talented, fitfully productive writer, who died in 2001 aged 49, would admire the concision of this one-hour adaptation. They've even lopped three words from the book's title. Running his Holistic Detective Agency, based on "the fundamental interconnectedness of all things", Dirk is broke and hopelessly chaotic. Stephen Mangan (Green Wing) is a spot-on Dirk, ably assisted by Helen Baxendale and Darren Boyd as sidekicks MacDuff and Susan. The plot builds to flights of fantasy from a simple case of a missing cat owned by pensioner Ruth, played by Doreen Mantle. From One Foot in the Grave's Mrs Warboys to Mrs Fishwick currently in Corrie, she's the connoisseur's vague old dear with impeccable comic timing.

Dirk Gently interview

As the BBC prepares to air its adaptation of Douglas Adams' Dirk Gently, here is an interview with Stephen Mangan, Helen Baxendale, Darren Boyd, and producer Chris Carey.

This is no ordinary sitcom. Laurence Howarth's likeable hero is Simon (played by Darren Boyd) an arms dealer. He's a nice man who always tries to see the other side of any argument and whom luck, or perhaps even a higher power, preserves. A big American arms firm, the best in the world, the most ubiquitous, the McDonald's of munitions, enters the takeover market. So he puts in for redundancy from his own employer, expecting a payout, longing for the day when he can give it all up and write music. Fate, however, has other plans. First of four episodes.

To summarise my thoughts now we're four episodes into its run: this is a really good sitcom that deserves wider attention. It's witty and has a reality to it, albeit with comical twists. The characters feel like actual people, so you therefore find yourself becoming invested in them dramatically. Alan Davies is good as Roland White, but it's Darren Boyd I'm really enjoying, as harassed sous chef Bib. The last few episodes have involved climaxes that poke fun at disabilities (a woman with one arm, Parkinson's Disease), which is a little alarming, but I can't say they weren't very funny.

I've never found Alan Davies as hilarious as he finds himself on QI, but I did laugh at his new sitcom Whites, in which he played Roland, the bored genius head chef of a country-house restaurant, lazing about dictating a memoir about his love for offal instead of getting on with some work. Admittedly, it wasn't great that he started with a joke from the back of the fridge ("If God didn't want us to eat animals he wouldn't have made them out of meat"), but he made up for it with sharper asides as he sparred likably with demanding colleagues, notably front of house manager Caroline (the great Katherine Parkinson from The IT Crowd) who thought Roland ought to do more vegetarian, and frazzled sous chef Bib (Darren Boyd), who thought Roland ought to do more of anything.

The plot - turning on the arrival of a top publisher who might take an interest in his book - kept hope and disappointment simmering nicely, while the arrival of an intense young apprentice (please don't let him turn out to be a vampire) offered slower intrigue. With Marco Pierre White's unruly hair and Jay Rayner's beard, Roland seems a composite of the sort of modern foodie we associate with frantic TV kitchens full of effing and blinding, so it was refreshing the way he suffered his fools - dim waitress Kiki, butterfingered Axel ("Careful with the plates - you're not at a Greek wedding") - like children with learning difficulties. Even the food looked real.

The very idea of a new sitcom on BBC2 makes my heart sink a little - all that British comic talent ploughing through a script in search of a gag - but it's probably best to start with low expectations. That way, when a programme like Whites comes along, one may be pleasantly surprised.

Given that it's set in the chaotic, high-pressure world of the restaurant kitchen, Whites is a surprisingly even-tempered thing. It stars Alan Davies as a self-absorbed executive chef at a country house hotel (he looks the part; in fact he looks exactly like Marco Pierre White), Darren Boyd as his demoralised sous chef and The IT Crowd's Katherine Parkinson as the catty front-of-house. There's a clumsy kitchen worker who spills things all the time, but there's also a creepy, ambitious agency cook named Skoose who adds some genuine menace. Whites occupies territory somewhere between dinnerladies and Peep Show (which I accept isn't much help to anyone trying to find it on a comedy map). Peep Show's Isy Suttie and Matt King (who co-wrote this) even turn up, as a hapless waitress and a dodgy meat supplier (he's dodgy, not the meat; not so far, anyway).

If it sounds surreal, inventive, original and hilarious then I'm over- selling it. It's gentle, subtly played, often funny and quite promising. At times it got a bit predictable, but I blame the leisurely pace, which sometimes allowed the viewer to catch up with the joke, and occasionally overtake it. In last night's episode the best laughs belonged to the minor characters, especially Isy Suttie's Kiki, who is kind, thoughtful and at least a half a bubble off plumb. "I remember my first day," she tells evil new boy Skoose. "I needed the loo but I was too scared to asked where it was, so I ended up going behind a gravestone in the chapel out back, and I thought I saw a ghost but it was just wee steam."

My main criticism of Whites is that it doesn't actually offer much new insight into the workings of a restaurant kitchen. Perhaps I've sat through too many episodes of Masterchef: the Professionals to be surprised, or even curious. Even the menu struck me as being a little tame. Comedy's one thing, but this show needs to take the cooking to the next level.