Claire Beale: Lovely ad, ITV. I hope it's not the only ray of light

Let's play a little game. I'm going to describe an ad and you've got to guess who it's for. Ready? We open on a grey, windswept beach. It's so bleak it gives you goose pimples just looking at it. There's a rag-bag group of kids walking with nowhere to go. They wave to the hobo in his beachside shack. He's cooking mackerel for his breakfast. This ad's shot like a movie; it feels like the beginning of something.

A boy picks up a pebble and throws it high into the dark sky. It punctures a hole in the clouds and a bright shaft of light pours out, bathing the children. They dance and laugh in the warmth of the spreading light. There's hope, optimism. Aw, are you getting a warm glow too?

The ad ends with the strapline "The brighter side". There's no price promotion, no special offer, no urgency. This ad isn't a desperate pitch for your purse. It's a classy piece of work, this ad. And that should narrow the field down for you quite substantially – not many brands do classy.

Ah, I sense that you're giving up, so let me tell you. It's for ITV1 – and a nicer bit of marketing you never saw from Britain's favourite commercial broadcaster.

Now, I can see why that might surprise you. Even if you've seen this ad, I'm not sure you'll believe who it's for. I'm not even sure I do, in spite of spending an hour talking it over with David Pemsel, ITV's marketing chief and proud father of the film. There's not an over-tanned, spangly-toothed C-lister in sight. Where's the cheese? And the cheap? Where's Ant'n'Dec, for Christ's sake? ITV1? Nah.

But it is. It's a bold, powerful film by ITV's ad agency Bartle Bogle Hegarty. Even better, it not only sells ITV1 (once you've got over the shock), it sells television. Because only TV (oh, all right, cinema too) can provide such a fabulous showcase for such bold, powerful films.

ITV's strategy, as you've probably gathered, is to own the territory of optimism, of positive shared experience, and of entertainment. And, in spite of all its troubles and flaws (costs to be cut by £245m, jobs axed, programming budget slashed by £135m), no commercial broadcaster owns entertainment and shared experience like ITV does.

Finally, ITV has the sort of showcase branding campaign that the BBC has led the way with. So I wouldn't blame downtrodden ITV executives from taking some extra pleasure at the BBC's current advertising, ahem, dilemma. Picture it: there was the BBC, with a lovely ad in the can to promote Radio 1. It's another stunning film from Fallon, a seriously smooth bit of promo work. Everyone was very proud.

And then the BBC starts to get a sound kicking. It gets a kicking for enjoying the licence fee when other broadcasters are forced to carry ads like Foxy Bingo to survive. It gets a kicking for having a Worldwide operation that makes money. It gets a kicking for being too successful.

So someone at the BBC decides that perhaps now isn't the time to be seen flaunting glossy ads that, let's be frank, aren't entirely imperative for the survival of the institution. The Fallon work looks just too scrumptiously expensive, too extravagant. Even though, apparently, it isn't. The BBC – with some justification – fears a backlash and quietly tucks the campaign into the back of the marketing cupboard for a while. And then, rumour has it, it asks its roster of ad agencies to start producing work that looks good... but not too good.

Of course, the BBC's agencies will carry on doing wonderful work that simply looks a little more modest. And those ads will continue to enjoy the privilege of being the only ads allowed to run on the BBC's airwaves, giving them terrific impact.

But, for now, it's time to applaud ITV for finding the strength to avoid all the usual fluffy clichés and third-rate cheeriness that have characterised the brand over the years. The thing is, it must work.