Jason Bourne director Paul Greengrass: I don't do social media

The new Jason Bourne film might feature a plot involving a global social network, but don't expect to find its director Paul Greengrass tweeting about it any time soon.

"It's not my thing," admits the 60-year-old British film-maker. "I don't know how to do it. I don't have any interest in it. I'm not of the generation that does it. I was one of the last people I knew to get a phone."

The film, simply titled Jason Bourne, reunites Greengrass with lead actor Matt Damon after their two previous franchise outings, 2004's Bourne Supremacy and 2007's Bourne Ultimatum.

Twelve years on from the events of Ultimatum, Damon's former CIA assassin is living "off the grid" when his old colleague Nicky Parsons (Julia Stiles) catches up with him, having hacked into the CIA computer.

Greengrass admits he didn't think he'd be back to make another Bourne film. "You don't want to come back and make one that's not very good - that's the terror of it. You've got to be sure you're doing it for the right reason."

When he started working on the script in 2014, the starting point was how much the world had changed since Bourne's last outing. Back then George Bush was US president and the Iraq war was in progress.

Since then, Greengrass notes, there has been a global financial crisis and the rise of smartphones, social media, electronic surveillance and cyber-intelligence. "We had to try and craft a story with Bourne in that landscape," he says.

A key theme in the film is the relationship between personal privacy and state security - there's a direct reference in the screenplay to US whistleblower Edward Snowden, and the plot involves a social network, Deep Dream, that pledges never to share its users' data. A bold claim, perhaps, in this digital age.

Greengrass and Damon had last worked together on Greengrass's Iraq war thriller Green Zone in 2010. So how does Greengrass describe his relationship with the actor after making their fourth film together?

"He's a close friend," Greengrass replies. "I have great trust in him as a person and as an actor. Making movies is both entirely ludicrous and incredibly hard. It's a preposterous way to spend your time.

"You give up a lot for the privilege of doing it and one of the things you get are relationships of immense trust that you see forged in situations of immense stress."

Warming to his theme, the director adds: "It's a circus life, the movies. It's a lot of travelling, a lot of antisocial hours, there's a lot of it that's about escaping from life.

"I have a vivid memory of Matt saying, 'I've given my life for this and I love it.' I was really struck by that simple statement of fact. It was like somebody saying I'm going to be a priest. It's a calling.

"You reflect on these things when you've finished a film because you feel a bit emotional."

Asked about Brexit, Greengrass - who voted Remain - says he has "a dim sense that it's not going to be good" for film-makers.

The industry, he says, was in "a very good place" within the EU.

"Will the damage be bad? I don't think anybody can say for sure. But any radical event like this can't be good for the development of a key strategic industry. But we are going to have to hope because the issues go beyond our industry.

"I'm a born optimist. We are going to have to pick ourselves up and find a way out of this mess."

Whatever happens, it's clear that Greengrass won't be taking to social media to give his opinion. Has anyone ever suggested he should sign up?

"They wouldn't because it would be so ludicrous," he laughs.

"It would be like telling me to wear a suit."

Jason Bourne is in cinemas from 27 July.