The writers of W1A (BBC Two, Thursday, 9pm) have a great eye for the worst bits of the modern BBC, but what prevents the comedy series from becoming just an inward-looking piece of television about television is that it's not just about the BBC.

The mockumentary, which was first shown last year, is set in the BBC, it features BBC staff and much of it is about the BBC, but it's also about life in a modern office - in particular, it's about how groups of well-educated professional people in offices can move further away from a goal while holding many meetings about moving towards it. W1A is also about the driving force of most office behaviour: the fear of being asked to do something.

The second series of the mockumentary picks up pretty much where last year's ended with the BBC's Head of Values, Ian Fletcher (Hugh Bonneville), and the head of PR company Perfect Curve, Siobhan Sharpe (Jessica Hynes), trying to deal with crises and usually making them worse. It's their glorious performances that makes it all work because the script itself is not the sharpest and there are even some jokes repeated from the first series.

In the first series, for example, a group of producers were faced with coming up with a programme idea for Carol Vorderman when Clare Balding was unavailable (she was making How Big Is My Dog?). The result was a show that was a bit like Countryfile and Bake Off, with a bit of The One Show thrown in just in case.

The same situation arose at the beginning of the new series of W1A when Entertainment Format Producer David Wilkes was faced with creating a follow-up to Britain's Tastiest Village and came up with a programme called Face Off. It was a bit like Britain's Got Talent and Family Fortunes with a bit of The One Show thrown in just in case.

The reason W1A repeated the One Show joke is that this is a mockumentary about the internal workings of the BBC and the joke is resting on truth. Just look at one of the genuine BBC shows coming up later this year: it's called The Great British Pottery Throw Down and it's a bit like Bake Off and The Generation Game with a bit of The One Show thrown in just in case. That's how the BBC works. The 10 O'Clock News is good, but wouldn't it be better if it was called The Great British 10 O'Clock News Off?

W1A has great fun taking the mickey out of all this, but what makes it awkward for the BBC, and brave of them to show it, is that there's a serious point at the heart of it, which is that the commissioning process is surrounded by people who clog the pipes and make everything go slower. "After working towards a drama for two years," says the narrator David Tennant at one point, "the project is finally nearing another meeting." It's a good gag, but it's a mixture of amusing and true; it's a joke that holds hands with the facts.