There are still ideas that don't really have legs, and still they are finding their way past the green light. Take Cockroaches, a new offering from ITV2. The idea of Freddy Syborn's script is that a nuclear holocaust has wiped out most of humanity, leaving teen couple Tom and Suze (Daniel Lawrence Taylor and Esther Smith) to roam the rural wastelands with their small child, conceived in haste on the night the bomb changed everything.

Essentially, it's the classic Seventies drama Survivors with jokes. That's the theory anyway, but alas the laughs are few and far between. The first few minutes, before disaster strikes, promised much. A newscaster warned of impending Armageddon, adding that no one had bothered to tell Africa and South America. The British Prime Minister (Robert Bathurst, not his first time as a comic PM: see also Hislop and Newman's comedy My Dad's the Prime Minister) was happier answering questions in Latin, a bit like You Know Who.

Spool forward a decade, and the future looked very like the past: jokes about not getting any sex, about in-laws, about cultural reference points (Suze reminisced about a blessed yesteryear in which "we had music, we had literature, we had Ant and Dec"). Suze supplied precious breast milk to both father and daughter, a joke much more creepily explored in Little Britain. The cast enlarged when they encountered a tribe of wood-dwelling dropouts led by Oscar (the ubiquitous Jack Whitehall), a Jafaican-spouting trustafarian ("Who talks like that?" wondered Tom). By the end of the first episode, attempting to enact the climactic immolation from The Wicker Man, he had been defeated. Tom accidentally hacked off his wanking finger.

There is a contingent of comedy fans - the really knowledgable ones with the excellent taste - for whom a little-seen BBC3 show from 2006 called Snuff Box represents the peak of British television. Matt Berry, who co-starred in and co-wrote that absurdist dark comedy, set in a gentlemen's club for hangmen, also stars in and co-wrote Toast of London. So is it the second coming we've been waiting for?

Slightly less knowledgable comedy fans, with slightly less excellent taste, may remember Berry as Douglas Reynholm in The IT Crowd or Dixon Bainbridge in The Mighty Boosh, but in this he finally takes the lead, playing portly middle-aged actor Stephen Toast, a role that allows full use of his booming voice. In the opening episode it was all going well for Toast: his agent, Janet Plough (Doon Mackichan), told him he'd won an acting award from a gossip magazine after 28 years in the biz, and women seemed to find him irresistible. So what if one was on bail for attempted murder and the other throws shopping trollies in canals for fun?

Where Snuff Box blended sketch, songs and character into something brand new, this felt more familiar sitcom territory - Toast even shares a bachelor pad, Men Behaving Badly-style, with Ed (Robert Bathurst). Yet while the "sit" was traditional, the "com" definitely wasn't. When Toast's flatmate brings home a conquest, it's not Leslie Ash from next door, but the Nigerian Ambassador's daughter, who has been transformed into a Generation Game-era Bruce Forsyth by a vengeful plastic surgeon.

The Berry sensibility was also retained with melodramatic camera zooms, a musical finale and a 1970s feel (albeit now located mainly in Toast's hairdo). This doesn't entirely get the BBC off the hook - they still need to commission more Snuff Box - but with the help of co-writer, Father Ted's Arthur Mathews, Berry hasn't had to restrain his imagination. Squeezing the larger-than-life luvvie Toast into a Sunday night sitcom set-up has just become part of the joke instead.

Like all PG Wodehouse adaptations, this suffers from the inevitable fact that it can never be as funny as the original, where the humour is not particularly in the ludicrous situations - here devoted pig owner Lord Emsworth strives to help the Empress win the Fattest Pig Contest despite the untimely imprisonment of her keeper. It's the way they're told: sheer effervescent clever wordplay, bubbling along at the perfect pace, with eccentric metaphors and slang words which jump off the page to charm away any reservations (that unfortunate Nazi collaboration business, or the fact they all basically tell the same story over 
and over).

Scriptwriters do try, forcing the best lines in there somehow, but even actors with the skill of Timothy Spall and Robert Bathurst can't make them sound as funny as they read. Spall looks exactly right as the lugubrious, befuddled Emsworth though, with Jennifer Saunders as his bossy sister (straying slightly too far into spoofing it up) and newcomer Jack Farthing as his cheerfully idiotic son. Frothy nonsense is hard to bring off and though I rarely laughed, it is an amiable and harmless distraction from a cold, broke January.

With their grand houses and period settings, it's a wonder PG Wodehouse's work hasn't been plundered by television more often. Clive Exton's exuberant Nineties adaptations of Jeeves and Wooster, starring Stephen Fry and Hugh Laurie, were highly successful, but there has been nothing since. However, judging by the iffy first episode of this new six-part series, based on the Blandings Castle stories and reworked by Guy Andrews, it seems that Wodehouse's precise comic world is pretty hard to pull off.

The problem lies not with the cast, which is certainly top-notch. Timothy Spall plays bumbling Lord Clarence Emsworth, more interested in pigs than people. Jennifer Saunders delights as his battleaxe sister Connie. And there's good work from Jack Farthing as Clarence's hapless son Freddie, and Mark Williams as Beach, the butler. But the episode can't quite sustain the necessary brio and the bonhomie eventually wears thin. Tonight's tale involves Clarence's rivalry with neighbour Sir Gregory Parsloe-Parsloe (Robert Bathurst) over a Fattest Pig competition and Connie's attempt to prevent niece Angela (Alice Orr-Ewing) from an unsuitable marriage.

A strong new one-off sitcom created by Father Ted writer Arthur Mathews and The IT Crowd's Matt Berry, who also stars as Steven Toast, legend of stage and screen. Having been a success for years, Toast is on his uppers after taking the lead role in a controversial West End play. Eager to get his career back on track he lets his London agent (Fiona Mollison) convince him to audition for a popular TV drama - the only problem being that the producer is in prison. Enjoyably bonkers, with a good supporting cast including Robert Bathurst and Tracy-Ann Oberman.

Those recalling Robert Bathurst's portrayal of John Le Mesurier in BBC4's Hattie might have thought him too good to be true. Au contraire. No one - from Clive Dunn and Ian Lavender to Michael Palin and JLM's third wife - has a bad word to say about a man who endured repeated cuckolding, perpetual career disappointments and terminal illness with a half-smile and drifted through life with an ineffably British sense of opaque understatement and vague melancholy. Much time is understandably spent on Dad's Army, but this doc also serves as a frustrating 'what might have been' for an underrated actor who ambled through a stop-start career with the same unknowable civility as he did his life. He's the man for whom 'keep calm and carry on' might have been invented.

Radio Times review

The 36th best TV show of 2011 according to the Radio Times.

A superb example of BBC4's curious but rewarding obsession with mid-ranking, mid-20th Century entertainers, and the misery success brought them. Hattie Jacques, trapped by sexist typecasting and her supportive but inert husband John Le Mesurier, welcomes a sexy young lodger (Aidan Turner) into the family home and proceeds to have an affair with him. As Jacques, Ruth Jones captured the desperation of someone who knows, deep down, that she's destroying herself, but can't quite stop. Robert Bathurst was just as fine as Le Mesurier, who could see what Jacques was doing but couldn't quite rouse himself to prevent her. A sensational-on-paper story became sober, classy and sad.

The Beeb's drama department has carved out a neat niche with its biopics of beloved British comedy stars: from Kenneth Williams and Tony Hancock to Frankie Howerd and Morecambe and Wise. This latest film, first shown on BBC Four in January, is a worthy addition. Gavin & Stacey's Ruth Jones stars in an acclaimed dramatisation of Carry On star Hattie Jacques's life. Though she played an austere matron on screen, Jacques's private life was actually rather racy. The story focuses on the early 1960s love triangle between Jacques, her chauffeur (Aidan Turner) and her husband, Dad's Army star John Le Mesurier (a heartbreaking turn from Cold Feet's Robert Bathurst) - whom she continued to love, even when she moved her toyboy into their bed. It's a bittersweet story, superbly acted, and followed by a repeat of Jacques's 1963 appearance on This Is Your Life.

In Hattie, Hattie Jacques (Ruth Jones) looked like she might be about to tell This Is Your Life host Eamonn Andrews to get stuffed, before composing herself and affecting modesty: "Oh Eamonn, they don't come much duller than me." Ha ha. What Andrews didn't know was that Jacques had just changed the man in the marital bed, despatching husband John Le Mesurier upstairs and summoning down their lodger.

No one knew this, This Is Your Life passed off without scandal, and in the divorce court, to protect Jacques, Le Mesurier pretended to have been the adulterer. "Thank you for ending our lovely marriage so beautifully," she said.

What a story! How civilised and quietly heroic and terribly British. Well, Le Mesurier was, anyway. The drama gave us nothing of Le Mesurier the actor and not very much of Jacques the actress.

Eric Sykes, in the run-up to BBC4's latest squint under the greasepaint of the great showbiz era, had complained about this.

But Hattie wasn't a sensationalist piece, just sad and moving and told in the usual Beeb 4 way with one classic car (the E-Type Jag driven by the fancy man, not his own), period lampshades, a fug of cigarette smoke, skinny ties, a dollop of casual sexism, a couple of old choons and, of course, a good script and some cracking acting.

Jones did that remarkable thing of making you forget all about her best-known role (Gavin and Somebody) but Robert Bathurst as Le Mesurier was even better, perfectly capturing his vagueness.

Swift production of the martini decanter solved most of his crises, although for having to tell his sons he was finally leaving he tried this sweetener: "I've got you both... pen knives."

I cheered when he remarried Jacques' friend Joan, completely forgetting that the latter's subsequent affair with Tony Hancock had been the subject of a previous Beeb 4 biopic. Pass the martini, old bean.

Has there ever been a more passive and diffident Englishman than John Le Mesurier? Last time he was dramatised was in a film about his best friend Tony Hancock, in which he stood politely by as Hancock ran off with Le Mesurier's third wife. Now he turns up in Hattie (BBC4) as Hattie Jacques's cuckolded husband (she was his second wife). Jacques - played in an exceptional performance by Ruth Jones - took in her used-car salesman lover as a lodger, and maintained a secret affair by the cunning means of slipping upstairs during the middle of the night. The scene in which she was finally discovered by Le Mesurier (a perfectly cast Robert Bathurst) in bed with her lover was a vision of tragicomic poignancy. He apologised for intruding and explained with consummate resignation that he was looking for his book - a James Bond novel. Seldom has the distance between reality and fantasy been so economically or movingly captured.