Theatre used to have a place on British television. For five decades from the 1960s onwards many stage productions were broadcast on TV. But interest among broadcasters dwindled post-millennium and it soon became a rarity. Which only fed the perception that theatre was inaccessible, that the West End was only for rich Londoners, an elite few.

Until, that is, somebody came up with the idea that you could broadcast live theatre in cinemas: utilising the combination of huge screens, great sound systems and the collective gasps and shouts of laughter that can only come from being part of an audience.

The Metropolitan Opera in New York was the first to do it, broadcasting HD performances simultaneously to cinemas in 2006, chalking up its hundredth simulcast production in October. Inspired by the success of the Met, the National Theatre launched NT Live in 2009, putting live theatre into 280 cinemas across 19 countries.

NT Live made its debut with Racine’s Phedre starring Helen Mirren which was watched by 50,000 people. The critics argued that you could never capture the heartbeat of a live production, that if you couldn’t smell the brylcreem to be showered in spittle sitting in the front row, then it wasn’t the real thing.

But NT Live approached livestreaming with the admission that, though linked, the mediums of film and theatre were wildly different. It hired the best multi-camera directors and production teams in the world, allowing them to rip out up to 300 audience seats to accommodate technical equipment on an epic scale; staging productions specifically for live broadcast and devoting rehearsal time, money and expertise into getting it right.

In seven years 6 million people have watched NT Live productions and its reach has grown to more than 2,000 cinemas in 55 different countries. It streams not just from its own theatre but from affiliate stages from the Wyndham and the Garrick, to the Old Vic and Manchester International Festival.

This week will see the broadcast of one the most hotly anticipated productions in years: Harold Pinter’s No Man’s Land, which reunites Sirs Patrick Stewart and Ian McKellen, following its transfer to the Wyndham Theatre in London. Suddenly a production that made its debut on Broadway, and which we had to wait three years before it transferred to the West End, will be simultaneously beamed around the world.

However, you can’t just set up a few cameras and expect a piece of theatre to work onscreen. “We have to give an experience to an audience that is better than in the theatre,” says Tim van Someren, a camera director who has captured As You Like It, Frankenstein and War Horse for NT Live. “I do mean ‘better’ because in cinema you’re guided. You won’t get splattered by blood in Macbeth but we will show you the best moments. It’s my job to make sure you don’t miss them.”

Live camera directors like van Someren sit outside the theatre in trucks housing a mobile production gallery (a huge bank of monitors) and orchestrate what the cinematic viewer can see: cut to camera 1 for a close up during emotional scene, camera 2 for the reaction etc.

Because the productions being filmed are normally sold out there can only be one rehearsal and, as happens in theatre, things change on the night: the timing of a line might alter, the facial expression you thought was coming might not arrive, so the director has to continuously adapt to how the drama is being portrayed, pre-empting what the actors are doing on stage, anything they might change on the night, getting the timing absolutely bang on.

Another NT Live film success was 'Hamlet' starring Benedict Cumberbatch (John Persson)

But there’s a degree of background work too. “We re-stage every play we put in the cinema,” van Someren says. “We completely re-do the lighting, we completely re-do the make-up and the wigs. The theatre director helps us to find the staging and we work together closely as, ultimately, I’m there to interpret for film what they’ve already created.”

The popularity of live theatre speaks for itself. On 25 November last year a live broadcast of William Shakespeare’s The Winter’s Tale beat Hollywood blockbusters to become the highest grossing film in Britain on the night of its screening. The three-hour-long play, starring Dame Judi Dench and Sir Kenneth Branagh, took in £1.1 million for its broadcast from London’s Garrick Theatre to 520 cinemas – more than the conclusion of the popular franchise, The Hunger Games: Mockingjay Part 2.

Similarly, the box office total for the NT Live film of the stage production of Hamlet starring Benedict Cumberbatch at one point overtook that of the critically-acclaimed movie adaptation of Macbeth with Michael Fassbender. However, because the live screening is put on once with a limited run of “Encore” re-plays, the numbers do not really compare with mainstream films.

The fear that streaming plays in cinemas would cannibalise theatre sales has largely been disproven. In fact, a 2014 report by NESTA that looked at data from ticket sales for 54 performing arts venues across England from early 2009, when NT Live was launched, through to late 2013, concludes that it appears to have boosted local theatre attendance in neighbourhoods most exposed to the live broadcasting programme.