Lights! Camera! Curtain! Action! A day at the National Theatre

Kate Youde sits in as it prepares a play for live cinema

"Four five two; four next," a woman intones into her headset, eyes focused on the camera script. Next to her, a man monitors the large bank of screens, which show what his five cameras are recording. So far, so very film. Yet the outside broadcast truck in which I am sitting is parked metres from the stage door of the National Theatre.

On Thursday, the theatre's production of the Arnold Wesker play The Kitchen will be beamed live into 130 UK cinemas as part of the third NT Live season, and this is the first of two camera rehearsals to ensure the film crew gets its angles right. In total, 700 cinemas across 22 countries will screen the performance, either live or as-live to take account of time differences.

Inspired by the Metropolitan Opera's screenings, NT Live launched in June 2009 when it transmitted Nicholas Hytner's production of Phèdre, starring Helen Mirren, into 280 cinemas. Since then, a global audience of more than half a million people has watched a National production on the big screen.

In the Olivier Theatre, five cameras positioned among the 1,111 seats are filming a full run-through of The Kitchen. (Theatre audiences get £10 off ticket prices to compensate for any disruption). Sitting in the truck during the second half, I watch as the action cuts between the cameras. Another crew in a second van, with even more buttons, deals with the sound feed from the theatre.

The Kitchen, set in a 1950s West End restaurant, presents a fast-paced challenge for the film crew. It is a piece of carefully choreographed chaos, with a cast of 31 actors bustling about the stage. Watching the eye-catching first half inside the auditorium, there is so much to take in – a bit of frying here, a conversation there, orders being chalked up on a blackboard, characters entering at the back of the stage.

I can see the whole scene, but I still feel like I'm missing something. And therefore the cinema audience, who can only see what the camera allows, will too. On the other hand, watching the second half in the truck, the camera close-ups often make it feel as if the actors are talking to me in a way I would not have felt in the theatre.

David Sabel, the National's head of digital media and producer of NT Live, says the project is designed to "honour the integrity of what's happening on stage". He recalls how Hytner told him it was like filming a sports match. "You take the camera to where you think the majority of the audience is looking," he says.

Robin Lough, the director for the screen, will watch the rehearsal footage with the play's director, Bijan Sheibani, to ensure both are happy with how the play will look on the big screen.

"Somebody said, 'I don't really see the point of it because it's neither the theatre nor cinema'," Mr Lough says. "No, it isn't, but it's clear it's succeeding as a different genre." More than 30,000 UK cinemagoers paid up to £15 to watch James Corden in Hytner's comedy One Man, Two Guvnors last month – an NT Live record.