This is a documentary about builders. You really need to prepare yourself for that. IT'S A DOCUMENTARY ABOUT BUILDERS. It's a documentary about people not turning up on time, and things falling down, and men standing around in your garden, looking oddly threatening. Rain falling on breezeblocks. Sagging tarpaulins full of holes. “The electrician hasn't turned up. I've got this mate called Ray who's very handy - he just hasn't got the official paperwork.” Sideboards loaded with 47 dirty mugs, all stained inside; like a mahogany lung full of Tetley cancer.

In short, this is a documentary that will make you feel increasingly tense and upset. Borderline angry. It will make you feel like, now you come to think of it, you probably could put off doing that loft conversion for at least another year. It's the equal and opposite TV reaction to Grand Designs - which usually has you Googling building firms by the first ad-break.

All told, Bobski the Builder is a pretty cheap bit of telly. Nearly two years after anyone really cared, Princess Productions is attempting to see which is best - British builders, or Polish builders. I know. How odd to obsess on it now, when we've had at least half-a-dozen nat- ional talking points (M&S pants, two wet summers, Cheryl Cole's marriage, Barack Obama, credit crunch) since then.

Putting aside any facts, figures, statistics, historical contexts or cultural examinations, Bobski the Builder decides to settle the matter by simply pitching a single British builder (Terry, pictured above) against a single Polish builder (Jarek) over the course of an hour. It's not so much a documentary - more Harry Hill shouting, “Which is best for builders - Poland or England? FIGHT!”

Of course, this being primetime Channel 4, the criterion is not, “Which nationality produces the most reliable and economic builders?” It is, instead, “Which nation produces the most loveable builders, with the most telegenic emotional ‘journeys'?”

For fairly obvious reasons (accusations of xenophobia; possibly having flaming pickled cabbage products pushed through their letterboxes at 5am), the production team flag up Polish builder Jarek's loveability very early on. He tells us his dreams. He laughs in a sweet, nervous way that makes you feel very protective of him. British Terry, on the other hand, is relegated to a couple of wry shots of him drinking tea. Terry slags off his client's house (“It's a shitty f***- ing house. It's not exactly a palace.”) Jarek, meanwhile, pays for extra plastering and pipework out of his own pocket (“They are a young couple. They need our help.”)

It's not merely clever editing. Jarek is genuinely likeable - cheerfully putting in ten hours a day, six days a week, to come in at £4,000 less than the British team - and you root for him and his team. Not least for his workmate Marion, who appears to be so poor, he can't afford a face. We never see it, anyway.

The British team, by contrast, sail three months over their deadline, £3,000 over budget, and spend all their time making cocky comments about clients and foreigners. The documentary makes its stance very clear: Terry=bad builder of yesteryear. Jarek=good builder of the future.

Except, it's not really that simple. Yes, Terry's extension might currently be under examination by the council - but Jarek's is scarcely perfect. He digs the foundations in the wrong place, until corrected by the homeowner, and then skimps on the insulation, which ends up with the entire concrete floor flaking and falling to bits. The homeowners are distraught - but the directorial line is that, ultimately, this just doesn't matter, because Jarek's not just building an extension - he's following his dreams.

Indeed, Jarek's emotional journey is pretty much unbeatable, as he ends up actually losing money on the project, can't pay Marion and Tomas a single penny, and leaves the site almost in tears. You feel awful for this cheerful, extremely hard-working, skint man. But you also wouldn't want him to build your extension. You obviously wouldn't want Terry to build your extension, either. To be honest, you'll just give up on the idea of having an extension, and get rid of one of the kids instead.

Like I said, it's a documentary about builders. It will make you feel tense, and upset. Perhaps borderline angry.

Cutting Edge: Bobski the Builder, Thur, Channel 4, 9pm

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