Last night's television: Sunshine, BBC1; Jack, A Soldier's Story, BBC3; Twiggy's Frock Exchange, BBC2

He’s not afraid of sentiment, Craig Cash. Indeed, he’s not even nervous about painfully cute, judging from the opening of Sunshine, BBC1’s new comedy-drama. As a wistful accordion theme plays on the soundtrack we see a Werther’s Original moment – a fathe rplaying cards with his young son– and a child’s voiceover said, “I’d like you to meet me dad.” There is a double-take coming, though, because the child speaking is not the one we can see on screen, as you’d assume, but the next generation down, and what we’re looking at is the start of a slippery slope. A gambling habit that begins with chocolate buttons is going to end up eating into holiday savings and the mortgage payments.

For the moment, though, that’s a long way off, and we’restill in the honeyed, slightly sickly glow of feel-good territory. “The one on theleft’s me granddad,” lisped the narrator, “and I think you’re going to love him.” Don’t bank on it, kid, I thought. The one on the right is Bob Crosby,Bing to his friends, played by Steve Coogan as if he’s the sunshine of thetitle. Bing is a chancer – addicted to the little flutter that gambling will inject into an ordinary life – and when we first encounter him as an adult he’s on a roll. His girlfriend, Bernadette, is about to make him a father and he’s won big on the horses. “One hundred pounds at 40 to 1, that’s £4,000!” he yelled disbelievingly. “Dad, I’m a millionaire!”

In terms of television drama, he hovers somewhere between a real person and a sketch character, an assembly of face-pulling and lovable fecklessness, which can never quite be pinned down to anything heartfelt. Arriving late at the hospital,he backed into thematernityward having a noisy argument with an imaginary interlocutor. “No, doctor! You’ve kept me waiting far too long already. I must see her now!” Then he turned to the disapproving nurses: “Now, where’s me Marigolds?”

If Sunshine stayed at this level – blokish, happy-go-lucky, relishing the dopey comedy of workplace banter andNorthern clubs – it would be perfectly amiable. Though some of the comedy is quite broad, the writers have a good ear for inadvertent, glancing comedy. “Good for you, love. You stick at it,” Bing said to his wife when she announced that she’d lost a few pounds at aerobics, “Rome wasn’t built in a day.” There are some nice sight gags too. “I don’t think they’ve quite got their heads round this four-four-two formation yet, have they?” said Bing’s father, watching a boys’ soccer game in which both teams are swirling after the ball like a tightly packed school of fish.

But there are signs that Cash and his co-writer, Phil Meaney, have another double-take in mind and that Sunshine is going to give way to gloomy and overcast. Bing’s wife’s boss is looking a little too appreciatively at his employee; his father (played by Bernard Hill) keeps having ominous funny turns and Bing’s creditors – not people to be fobbed off with a larky accent or a karaoke version of “Can’t Live without You” – are starting to get tough. More significantly, Bing is beginning to gamble with our goodwill, by stealing the money his long-suffering wife has set aside for a trip to Disneyland, and losing it all after being lured by someone he thinks is a friend into a gambling sting (another neatly plotted double-take). Cash isn’t afraid of sentiment here either, cutting between the distraught Bing and his weeping wife as Luciano Pavarotti belts out a lachrymose Italian pop song on the soundtrack. By now, though, it’s possible to believe that these people are real enough to care about, and real enough to feel some pain.

No question about that in BBC3’s Jack: a Soldier’s Story, in which Ben Anderson followed up his memorable Panorama film about the fighting in Afghanistan’s Helmand Province with a film about what happens when heroes come home and find they can’t cope with what they’ve experienced, which in Jack Mizon’s case included the death of close friends. It ended – after disciplinary action and a court appearance for GBH – on a very faint note of hope. It also pressed home the continuing pertinence of Kipling’s take on the soldier’s double life: “For it’s Tommy this, an’ Tommy that, an’ ‘Chuck him out the brute!’/ But it’s ‘Saviour of ’ is country’ when the guns begin to shoot”.

I would have to have an orchidectomy and prolonged hormone treatment to really enjoy Twiggy’s Frock Exchange, but even in my unaltered state I can see it’s a terrific idea: credit- crunch economics married to a walk-in dressing-up box. I’m not sure men should even be allowed to watch, since it implies that all women are fashion-dazed airheads who get all giddy in the presence of a pair of Manolo Blahniks. But I suspect an appreciative female audience will enjoy it precisely in the spirit intended - a girly night in.