Georges Polti, following Goethe, maintained there were only 36 dramatic situations, and that all storylines were reworkings of them.
It's clear that few people in the British film industry have got very far into Polti's book, because time and time again we find that British films admit of only two plotlines. They are:
1. It's really terrifically brutish being working class
2. It's really terrifically spiffing to be middle class
Take the two current British releases. Calendar Girls is the heartwarming tale of how supportive and daring some nice middle class ladies can be (hurrah!), while Blackball relates how a nasty common chap gets too big for his boots (boo!) and gets taught his place (hurrah!). The two films are even written by the same man, Tim Firth.
One obvious reason why producers stay faithful to this formula is its success; as a wander through the history of recent British cinema will show.
Four Weddings and a Funeral (it's really spiffing down south), Trainspotting (it's really quite grim in Scotland - see also Sweet Sixteen, Young Adam ...), Harry Potter (it's really quite boffo at public school), Notting Hill (it's great being middle class in west London), Pure (but it's not so nice being poor in east London).
Admittedly the last one didn't sell so well, but you get a feel for why it got backed at all. Again and again, British audiences lap up these two opposing conceptions of our national life.
It's as if we can only conceive of ourselves as posh people - who are generally happy, if a little endearingly confused - or vile, wretched commoners.
The worst synthesis of this is perhaps Billy Elliot, about a poor boy's struggle to become middle class, which will make him happy.
But even a marvellous film like Bridget Jones's Diary is complicit; posh people can be bounders, but they're terribly attractive, and oh if only Bridget could get to grips with how terribly difficult it is to be properly posh and snare herself a barrister (not an oily foreigner like her mum did), then she too could be happy.
There are many honourable exceptions; Secrets and Lies, Dirty Pretty Things, Bend It Like Beckham, Human Traffic; all very different films, but none of them infected with this patronising view that we're all either brutish pond life stabbing each other in the back, or bumbling toffs trying to get on and get married off. But somehow these movies - successful as they may be - rarely get elected as "event movies".
The worst thing about all this is knowing that it's not going to get any better. The big, big British film of the winter is going to be Love, Actually, a script by Richard Curtis (Four Weddings, Notting Hill ...), starring Hugh Grant (Four Weddings, Notting Hill) as a posh man (Four Weddings, Notting Hill) in a romantic predicament (Four Weddings, Notting Hill).
Specifically, Hugh is the prime minister, and he fancies his tea lady. Quite apart from whether or not this makes any sense in modern Britain (surely Downing Street catering services have been outsourced as part of a best value initiative?), is this the best we can do in the 21st century? Prince marries scullery lass?
You may say I have a chip on shoulder, that I'm a joyless curmudgeon. You may point to the merrily ringing tills as first Calendar Girls and then Love, Actually are taken to the bosoms of the great British public.
And if you're a film producer, you're almost certainly best advised to ignore this rant. But it's a lonely business being right in a world where everyone else is wrong.