It takes a special kind of love to move into the lodger's room in the attic while your wife makes hay with her fancy man in the master bedroom. But that was the peculiar domestic set-up at the conflicted heart of Hattie, the true - yes, true - story of Carry On comedy legend Hattie Jacques.

Ruth Jones certainly looked the part of Jacques, all twinkly eyes and comfortable cleavage, her sunny smile masking the frustration of a career cul-de-sac. 'I know my casting; I'm the frigid fat girl,' she complained, acknowledging her role as the nation's favourite chubby, a 1960s Dawn French, if you like.

But though she gave a good impression of warmth, Jones's Hattie strayed a touch too close to heartless bitch for this remarkable story to fully convince. The heart of the tale belonged to wronged husband John Le Mesurier, played by Robert Bathurst with just the right measure of unqualified love and ruffled dignity. 'He's too vague to be unhappy,' claimed Hattie, granting herself licence to cheat, but Bathurst's nuanced performance turned Le Mesurier's vagueness into a self-protective shield.

As a period piece Hattie worked superbly, its glimpses of Carry On film sets, with Marcia Warren scene-stealing as an embittered bit-parter ('I'm sick of this batty old lady s***') a diverting treat. But we didn't get enough of the self-esteem issues that bedevilled Jacques and led her to jeopardise a happy marriage by falling for a devilishly handsome wheeler dealer who made her squeal between the sheets. She fell rather too easily.

Desperate Romantic Aiden Turner certainly looked the part, all moody scowl and hairy chest, but his gor-blimey accent was comedy working class. 'I'm not a bit of rough!' he exploded but that's exactly how he came across, fine for a lusty leg-over but hardly a prospective long-term partner. Which was why Hattie kept her husband in the house to talk to, during the intervals between the sex olympics.

As I said, peculiar. It fell apart when Le Mesurier met a new love, though everyone remained remarkably civilised, and Hattie's bit of rough ultimately left her. It was all quietly sad and a noble attempt to tell a tricky tale. But I never quite fell for it.

Ooh, matron! The real-life bed-hopping antics of Hattie Jacques were a far cry from the sex-starved battle-axe she played in the Carry On films.

Gavin and Stacey's Ruth Jones pours herself into a series of shiny sixties frocks and some sexy corsets for this handsome one-off biopic. Meanwhile Aidan Turner - of Being Human and Desperate Romantics fame - is transformed after a run-in with the hair-straighteners into her toyboy, bit of rough John Schofield.

When Hattie divorced Dad's Army star
John Le Mesurier (played by a very well-cast Robert Bathurst) in 1965, it was reported that he had cheated on her.

In fact, the mild-mannered Le Mesurier was the innocent party while Hattie had been living the best of both worlds - moving her husband upstairs to the attic, and her lover - a cockney car-salesman - into her marital bed.

It doesn't exactly show Hattie in a favourable light. How could she do it to the lovely Le Mesurier? As she explains to a girlfriend while Schofield hunks about the garden, bare-chested in shorts: "Ooh, look. Him! With me!"

Ruth Jones is mesmerising as Hattie Jacques, the beloved comic actor and Carry On star, who became part of a domestic ménage with her adored husband John Le Mesurier and a sexy younger man, John Schofield. The story is irresistible: Schofield (played by Being Human's Aidan Turner) is a second-hand car dealer who meets Hattie after a charity event while she's filming Carry On Cabbie and the two are quickly in the grip of an electrifying sexual passion. Bizarrely, even incredibly, Schofield moves into the Le Mesurier family home and the marital bed, with John Le Mesurier banished to the lodger's room in the attic. Yet Stephen Russell's script judges no one as it reveals a marriage that, in its own strange way, was rock-solid: Hattie and Le Mesurier shared a lifelong devotion after their divorce. Ever the gentleman, Le Mesurier (Robert Bathurst) takes the blame for the break-up. Hattie is a touching drama that, for once, doesn't perform a hatchet job on an adored British comedy figure.

The Carry On star and much-loved comic actress Hattie Jacques might have often been cast as a stern matron, a battle-axe even, but Stephen Russell's bittersweet drama reveals a lustier, naughtier side to her character. There are elements of artistic licence in his storyline and Hattie might have benefited if it had offered a broader spectrum to Jacques's life, but this tightly focused film is driven by an exquisite performance by Ruth Jones.

The story details the clandestine affair Hattie embarked on during her marriage to the actor John Le Mesurier (Robert Bathurst) at a time when she was at the height of her popularity. Jacques might have hated being overweight (she longed to be a ballerina), but her size merely seems to fuel her desire as she is readily seduced by the young John Schofield (Aidan Turner) - a handsome, rough and ready used car dealer. Desperate to avoid any kind of scandal ("You British never forgive people who like a lot of sex," says her lover), Jacques, not wanting to lose either man, tries to keep the affair a secret. When Schofield becomes a lodger in the Le Mesurier household, she's forced to divide her time between her tolerant husband - who is portrayed, perhaps a little unkindly, as being lovably hapless and never far from a drink - two children and demanding lover.

It's a beautifully observed production with a sharp script, but the highlight is an astute characterisation of a fragile, highly sexed Jacques.

Ever wondered what Carry On actress Hattie Jacques might've looked like in the throes of sexual ecstasy? Then look no further than BBC 4's latest "tears behind the laughter" biopic, hattie, which takes a mildly scurrilous peek at a peculiar episode from her once private life.

Though hidden from the public during their lifetime, it's now common knowledge that Jacques and her husband, beloved British comedy actor John Le Mesurier, were embroiled in a bizarre love triangle involving cockney chauffeur John Schofield.

The film shows how Jacques was seduced by this ravishing charmer, who then moved into her marital bed while Le Mesurier - in an almost farcical display of gentlemanly English stoicism - was banished to a guest room.

Jacques obviously adored her husband, so what was she thinking? Unfortunately, writer Stephen Russell doesn't provide many answers beyond suggesting that, insecure about her weight, she was flattered by the attentions of a younger man. It all feels rather glib.

Though Schofield (Being Human's Aidan Turner) is depicted as having genuinely fallen in lust with the vivacious actress, Russell also suggests that the material trappings of her celebrity lifestyle proved just as enticing.

As for Le Mesurier, he's portrayed as an exasperating cuckold incapable of functioning without his wife's support. The public humiliation he avoided in life is now exposed for all to see: hardly the point of his sacrifice.

Ruth Jones is fine in the lead role, although she doesn't have much to work with. Maybe Jacques really wasn't that complex in real life, but there must have been more to her than these superficial character traits. She's depicted as warm and charitable, with a girlish sense of fun, but an immature recklessness when it came to her own family. And that's it.

Robert Bathurst steals the acting honours as Le Mesurier, suggesting acute sensitivity beneath those famously vague mannerisms. But his character never really comes alive either.

Although not bad as such, Hattie suffers from rather bland execution. It recounts a strange, voyeuristically interesting story, but rarely engages on an emotional level.

The start of the new series of this sitcom is neatly timed, considering the recent announcement of lottery funding for the restoration of part of Bletchley Park, the epicentre of Allied decoding efforts during the Second World War. In the series, which is set at the complex during the war, the feuding among the code breakers is rampant. Archie (Tom Goodman-Hill), a revolutionary socialist, clashes with Charles (Robert Bathurst) over a long-held grudge, while the young maths prodigy Gordon (Fergus Craig) attempts to keep the peace.

Mutual Friends started with a suicide but ended with a fire engine. Carl's suicide was the writers' device with which to bring together his surviving friends, Martin, played by Marc Warren, and Patrick (Alexander Armstrong). Martin was the worrying type and he had loads to worry about: not only was he about to lose his job as a solicitor but his wife, Jen (Keeley Hawes), announced that she had slept with Carl and that their marriage was in trouble (all Martin's fault).

Patrick also had his problems: a personal financial crisis had got his E-Type Jag repossessed and one of his business partners was edging him out of his own Boden-style catalogue company while edging himself into his former girlfriend's knickers. The worrying thing about Patrick, buoyed along by ego and testosterone, was his inability to worry. Yet this follicly challenged Lothario was not, it transpired, irredeemably self-centred. It was he, after all, who was responsible for the fire engine's comical appearance - called not to hose a conflagration but to fulfil Martin's disgruntled young son's ambition to ride on one.

Warren, Armstrong and Hawes are watchable actors but you couldn't help but wish their parts had been occupied by Jimmy Nesbitt, Robert Bathurst and Helen Baxendale and that, as in Cold Feet, there had been room for a genuinely funny subplot (as regularly supplied by the actors Fay Ripley and John Thomson). Nor could you fail to spot how inspiration was running out even as early as episode one. Martin, for instance, kept being overheard saying things that he shouldn't by the people he was badmouthing. Only once could you accuse the programme of inventiveness and that was in the character of Carl's widow Leigh, played with cheerful understatement by Claire Rushbrook, who had clearly lost her how-to-grieve manual and went round saying how 'cross' she was with him.

My hunch is that Mutual Friends will keep its audience, not least because it is unusual in putting at its centre male rather than female friendships. But how, even as I watched its titles (as ripped off from Mad Men), I wished for more subtlety, more black humour, more depth of emotion!

Mention the crack squad of code breakers working from Bletchley Park in the Second World War and thoughts turn to the brilliant young men of Robert Harris' novel Enigma. The team in this sitcom are more of a crap squad and have been placed inside Hut 33 where their incompetence - more social than work-related - can be safely hidden.

It's a bit like Dad's Army in as much as the humour is gentle and the characters are intrinsically appealing. But the humour is far saucier: Robert Bathurst plays an officer terrified by a sex-crazed barmaid, for example, while the jokes about gay sex would never have been allowed in Walmington-on-Sea.

Not only is Hut 33 one of the very few radio shows set in a shedlike atmosphere, it's also very funny.

I'd heartily recommend tuning in as the first series was a hoot and the cast, including Robert Bathurst and Olivia Colman, are excellent.

The performances are spot-on. Robert Bathurst is perfectly cast as the arrogant but suffering Mark Taylor, his desperation evident from the outset. Bathurst is almost too convincing with Moffat's razor-sharp dialogue. But no sooner does the tension build than it is dissipated by a one-liner.