Joe Cornish on how a mugging inspired Attack the Block

The film's teen gang was played by mainly inexperienced actors

Director Joe Cornish talks about the inspiration behind his sci-fi film Attack the Block - and why he turned a gang of hoodies into movie heroes.

It all started with a mugging.

It was October 2001 and Joe Cornish (of Adam and Joe radio show fame) was relieved of his mobile phone and wallet by a gang in his native south London.

Ten years on, Cornish's debut movie kicks off with a similar scene in which nurse Sam (Jodie Whittaker) is robbed at knifepoint - just as an alien creature crashes out of the sky.

Do the masked muggers extend a hand of welcome to the extra-terrestrial visitor?

Of course not. They beat it to death, take its carcass to the top of their tower block and debate how much they might get for it on eBay.

Of his own mugging, Cornish says: "It was less intimidating than the one I stage in the movie. But what struck me about it was how young the kids were, how unreal and ritualised the situation was.

"It felt like a little play we all knew how to perform. I could see that the boy was young and I'm sure I was on same level as Call of Duty as him."

Joe Cornish (pictured above at the Attack the Block premiere in London) grew up with cult movies

In Attack the Block, Cornish goes against usual cinema conventions and stays with the muggers and not the victim.

"I thought it would freak the audience out to follow a group of people who they feel ambivalent towards," he says.

"Most movies work their butts off to make their protagonists sympathetic. I thought it would be interesting to not do that."

More than that, the hoodies take on heroic status - though Cornish is adamant he's not glamourising gang culture.

"Mugging is a reprehensible thing to do and it was quite profoundly traumatising. It breaks an unspoken contract you have with society, so in no way is this film an apology for that action.

"But it is an explanation of why a kid like that might decide that an action like that is feasible."

Street slang

Attack the Block also gives Cornish the opportunity to pay homage to the movies of his youth.

Nick Frost stars in the film as a seedy drugs dealer

He reels off a list: ET, Gremlins, Critters, Tremors, Predator, The Thing, The Outsiders, Rumblefish, Warriors and Streets of Fire.

"John Carpenter is a huge influence - especially Assault on Precinct 13," he adds. "It's a siege movie with a strong sociological subtext."

In one key shot in his movie, Cornish's camera glides past the titular tower block as if it were a giant interplanetary craft.

"The tower blocks where I grew up have always looked like enormous spaceships. They were built in the spirit of huge optimism and futurism," says Cornish.

"In movies like Clockwork Orange or Logan's Run that architecture used to speak of escapist things - but now it speaks of grimness, so I wanted to flip it back round."

Despite growing up in Brixton, Cornish admits he is "a bit less street than Prince Charles".

In order to develop the real street lingo used in by the gang in Attack the Block, he spent months talking to youth groups in south London.

"We built a lexicon of about 10 words which we use repeatedly. Sci-fi is full of alternate languages, whether its Na'vi in Avatar, or Klingon. Words like dilithium crystals or Hoth - they are meaningless but they have huge meaning to sci-fi fans."

As well as his feature film debut, Cornish has co-written the script to Steven Spielberg's forthcoming 3D film, The Adventures of Tintin: Secret of the Unicorn.

So is this hello Hollywood, goodbye Adam and Joe?

"Not necessarily. I very much try to do everything. I feel massively loyal to Adam and all those listeners. But we've both done lots of solo stuff and [his voice drops to a whisper] we can't stay on the radio for ever.

"There's only so many times you can hear our flippin' songs."

Attack the Block is out this week.