Since its first broadcast of Phèdre , with Helen Mirren in the title role in 2009, National Theatre Live has brought almost 50 plays to 4 million people worldwide in 2,000 cinemas.

At a London Centre event in early March, Executive Producer David Sabel and Technical Producer Chris Bretnall discussed NT Live with journalist George Jarrett.

During the evening, the audience were treated to clips from NT Live broadcasts, including War Horse, Othello and The Curious Incident of the Dog in the Night-Time.

NT Live was inspired by the success of the Metropolitan Opera in New York, which, starting with The Magic Flute, has been screening performances live since December 2006. “A live and a shared experience on a big screen in a cinema, although it can never be the same thing as going to the theatre, retains the DNA of live performance,” said Sabel. “The great gift of NT Live is that you’re seeing the intimacy, the nuance and the detail of the performance.”

Live screenings widen access to the theatre. “We have national in our name,” said Sabel, who has been involved since the first days of NT Live. “The exciting opportunity for us was that we were going to be able to reach more people around the country.”

The pilot season of four screenings was a year in the planning, with production kept in-house mainly for artistic – but also financial – reasons. “We wanted to preserve the integrity of what was being created on stage,” said Sabel.

In-house production, reckoned Bretnall, is vital. “It is the National producing content for the National; it’s not a big, nasty broadcaster coming in, taking over and doing what the hell they like – we have 100% buy-in from the team at the National,” he said.

Bretnall, who served 19 years at BBC Outside Broadcasts before founding his company, Creative Broadcast Solutions, worked with the Metropolitan Opera on its first two live seasons. Like Sabel, he has been part of NT Live since Phèdre.

Bretnall said the production team have “almost total freedom to put what we want where we want it, to try and bring a story that has been developed for the stage on to the big screen.

“The National Theatre gives me and the directors the flexibility to take out seats, build as many tracks as we like and have as many cranes as we need to be sympathetic to the story that’s being told on the stage.”

The production team watch the play repeatedly. They have two dry runs – filming the actors performing without an audience – to work out the best camera positions, and to perfect the lighting and sound. The production is filmed for live relay, via satellite, to UK (and some European) cinemas.

NT Live has expanded from its Southbank base to film Coriolanus from the Donmar Warehouse and A Streetcar Named Desire from the Young Vic.

Each broadcast costs £250,000-£350,000, revealed Sabel. NT Live, he added, “is now generating revenue for the National and, very importantly, for the artists, because they are all part of the profit share”.