Tony Gilroy has been working in Hollywood since 1986 when he sold his first script as a vehicle for Chuck Norris. Although that film was never made, he fast became one of the biggest names in screenwriting, clocking up credits such as Dolores Claiborne, Armageddon and the three Bourne movies.

He directed his first film, Michael Clayton, in 2007 and scored Oscar nominations for script and direction, but even then he was nervous that another writer would catch on to the subject of corporate espionage before his pet project, Duplicity, could reach the screen.

'For the last three years I've been worried there'd be another corporate espionage picture out there,' he says. 'It seemed such a rich topic. I was sure we were going to miss it and once that happened, it would kill my script.'

Duplicity was originally set up with Section Eight six years ago as a directing gig for Gilroy's friend Steven Soderbergh but eventually, after Michael Clayton, he opted to direct it himself.

He was introduced to Clive Owen by George Clooney at a party held by Clayton producer Jennifer Fox, midway through the shoot of that film. 'Clive was in the neighbourhood and George introduced us. Out of the blue, George said Clive should do Duplicity. He'd been in the first Bourne film but I'd never met him, so we talked, and I fell in love with him immediately. He became my co-conspirator for the two years we were trying to get the movie made.'

Having tweaked the script to make the male character British, Gilroy went straight to Owen's pal and Closer co-star Julia Roberts to take the female lead but she had just become pregnant. 'I was so into doing the movie with Clive that we basically both went off and did other things and pledged to reconvene when we could put this back together.'

When Gilroy and Owen did finally reconvene, they went back to Roberts and she was ready to commit. The movie was an easy greenlight for Universal, home of the Bourne franchise.

Gilroy says his fascination with dark corporate deeds arose on films such as The Devil's Advocate and Proof Of Life as well as Enemy Of The State on which he did a rewrite.

'When we did Proof Of Life, we got deeply involved with control risks out of London and got to know a lot of people in British intelligence. We watched these people go into the private sector and later I would call people who were my sources for the Bourne pictures and they were all going private.

'I can't imagine there's a major multi-national corporation that doesn't have some sort of competitive intelligence office, if nothing else to defend themselves against the other companies who may be attacking them. Everything in this movie is true. It's a pretty simple Google.'

Meanwhile, with Duplicity, Gilroy once again challenges the audience with complicated plotting and time structure. 'If you don't walk out in the first 45 minutes, everything is explained in this movie,' he says. 'Everything ties up and makes sense and hopefully there's some fun in not knowing exactly what's going to happen. I get so tired of going to movies where not only I know what's going to happen but my 12-year-old daughter knows what's going to happen.'