British film-makers! Put down those clapperboards and pay attention because David Cameron, who happens to be a huge fan of your work – assuming you're making The King's Speech II – wants you to focus on films likely to be a "commercial success". Which presumably is the last thing you want.

Cynics say Cameron knows squit about British films. When that photo of SamCam and Michelle Obama having a coffee morning in the Downing Street flat was released, there didn't seem to be many British films in the Cameron DVD collection. Not even Carry On Screaming. Mainly US TV boxsets. Oh, and he owns the film Armageddon on DVD. It's hard not to judge him for that.

To be fair, the photo was taken before The King's Speech had come out on DVD. Apparently he bought 26 copies of that. Not deliberately – he thought the disc was sticking so he kept buying it again and again, until he realised the lead character had a stutter.

Anyway, Cameron's advice for film-makers runs as follows: go mainstream. For years, you've held audiences in contempt, deliberately making your works obtuse. You even have to be cajoled into taking the lens cap off because you'd rather the repellent "viewers" sat there in pitch-blackness, trying to piece together the story from the soundtrack alone.

Not that there's a "story" anyway. The notion of a coherent plot offends your snooty arts-hole sensibilities. No one's saying you have to signpost everything, but for God's sake attach some clear labels. Look at The King's Speech. For one thing, you can look at it: no lens caps left on there. What's more, the story is simple. The world's most important man can't speak properly, so he gets taught to speak properly. But then disaster strikes! It looks like he might not be able to speak properly after all. Finally, in a triumphant climax, he speaks properly. It's a feelgood ending for everybody, apart from the 450,000 Britons killed in the war he just announced on the radio.

Feelgood endings are another mainstream necessity. Why go to the cinema to watch a film about desperate, blighted lives, when thanks to Cameron you're already living one – in cutting-edge 3D. Not that directors shouldn't make films about ordinary paupers, provided they're left smiling at the end. One of the main reasons David Cameron enjoyed The King's Speech is that it showed him how a man less privileged than himself overcame his lowly breeding and learned how to conquer a stammer. Compare that with a film such as Fish Tank. People said Fish Tank was brilliant but it didn't outperform Transformers: Dark of the Moon, because they neglected to put any 200ft robots in it, and no one victoriously punched the air at the end.

The British film industry needs to have the courage to think inside the box, sinking its money into guaranteed box-office hits such as Absolute Beginners and that Alien Autopsy comedy starring Ant and Dec. If you want commercial success, look at what's packing them in down the multiplex, and give them more of the same – only morer and samer. People hate variety. They don't want anything "new".

Superhero films are guaranteed box-office gold – so let's make a British one: a Dark Knight facsimile about a vigilante Beefeater in a rubberised outfit who lives in the Tower of London with an army of ravens. Also, how about Paddington Bear as a wisecracking CGI hero? The marmalade sandwiches he enjoys won't "read" overseas, so we'll replace those with peanut butter and jelly, but otherwise he's exactly the same loveable British Paddington Bear, minus the bit about him being an immigrant from darkest Peru. Also, he wears sunglasses and says "woah, THAT's godda hurt!" and is voiced by Ashton Kutcher.

Actually, Cameron isn't an utter philistine. He approvingly referenced the Lindsay Anderson film If … on the Today programme. Which is odd because If … is precisely the sort of film that would never, ever get made if his advice were heeded.

No one sets out to make a box-office flop. The problem with British films isn't a failure of ambition – it's the challenge of getting the damn things seen in a world filled with chain multiplexes programmed by monolithic distributors. Without distribution, no one sees your film. And without a huge marketing engine behind you, without a cookie-cutter similarity to the last big thing, the distributors often ain't interested.

The King's Speech was a superb film, but it's essentially Rocky for stammerers. Patriotic, yes: but we've made other, more forward-looking British films by ignoring the box office and taking risks. This Is England was a big British hit after years of low-budget risks from Shane Meadows. Kidulthood was a big British hit because Noel Clarke risked a film resembling nothing else in the multiplex. Four Lions, Shaun of the Dead and The Inbetweeners Movie were big British hits, the success of which can be traced back to risks taken on television: Chris Morris, Spaced, and the original Inbetweeners sitcom – niche comedies on minority channels. The mainstream came to them. Not the other way round.

If Cameron is serious about wanting our film industry to make more money, he should leave the ball-breaking yap about profits to Glengarry Glen Ross, and instead take the long view: nurture the creative talent of tomorrow – from film-makers to games designers. The upcoming generation is being squeezed harder and has fewer choices than ever. Unleashed, they could create things neither Cameron nor myself could possibly begin to imagine. Give them a playground, let them make mistakes, and give them time: they'll generate glorious failures and unprecedented moneyspinners. British ones. Which Cameron can proudly display on his shelf. If there's room between Armageddon and his 26 copies of The King's Speech.