It’s like buses, isn’t it? One minute there’s no sight of a Peter Shaffer play in the West End. The next minute his three biggest hits are trundling back into town within a year of one another. One minute there’s not a sight to be seen of the postwar provocateur Harold Pinter (likes pauses, doesn’t like war, anyone remember old Harold?). The next his work is coursing through the veins of a grateful theatreland. There have been two big Pinters already this year — and there are at least four more to come.

It’s the way of the West End. A few years ago, in the run-up to the centenary of his death, it was Ibsen. Then there was that brief Schiller revival, after decades — centuries? — of neglect. Shakespeare and Chekhov are givens, permanent presences on account of ineluctable genius. But Tennessee Williams has inched his way back; John Osborne is seeping through too. Who next? Stoppard? Strindberg? Cooney?

How does it all work, anyway? Why did three separate producers get West End rights — harder and more expensive to get than regional rights — at the same time for three Shaffers? How did everyone collectively remember just how great Pinter is, all at the same time?

The answers are in the very nature of big revivals, which after all make up the bulk of London’s straight plays. Go to the National Theatre tonight and you’ve a choice between shows from 1676, 1944 and 1997. If it’s not famous faces we want from a trip to the theatre, it’s famous writers, famous texts. But how, from a forest of options, do theatres choose which ones to go for?

1. It’s the author’s birthday

Peter Shaffer turned 80 last May. That prompted producers to think about him again. But it also prompted him to reconsider his own visibility. The dearth of West End Shaffers was about his reticence rather than a lack of offers. “From the initial request to the first night, it took us eight years to get the show on,” says the producer of Equus, Dafydd Rogers. “I can’t say why he allowed three of his plays to be produced in the same year. But I suspect the birthday has something to do with it.” See also Osborne’s The Entertainer and Pinter’s The Dumb Waiter: both have returned for their 50th birthdays.

2. The play is declared newly relevant thanks to the startling insights it offers on the War on Terror

We’re past the time when the RSC seemed to bung sand-bags on stage for every production, or when Adrian Lester trundled on in a tank for Henry V at the National. But theatres need to prove to the examiners — sorry, audiences — that digging backwards offers a new angle on the present. “It’s hard to put your finger on it,” says Michael Attenborough, the artistic director of the Almeida theatre, “but certain authors just seem to come round again because what they say seems pertinent to the time. You think, ‘Aha, I’m going to do that one!’ And then you ring Michael [Grandage] at the Donmar or Nick [Hytner] at the National and they say, ‘Oh, we’re doing him too’.”

3. It’s a sequel

Producers, like the rest of us, are suggestible. They see a play by so-and-so, they go, “Of course! So-and-so!” and spend the weekend in bed reading the Complete Works of So-and-So, looking for something with a part for Derek Jacobi in it. “You can be influenced by what’s going on elsewhere, absolutely,” Attenborough admits. “Your antennae are out there.” But if it’s a modern classic you want, you have to snaffle the rights fast. That’s why the producer Sonia Friedman won’t be adding to the current trio of Tennessee Williams revivals ( The Glass Menagerie, The Rose Tattoo, Lovely and Misfit). “All the great Williams titles, the rights are gone,” she sighs. “The ones still knocking around, there’s usually a reason why they’re still knocking around.”

4. “The clown who wants to play Lear”

Who thought that Sean Bean should play Macbeth? Why, Sean Bean, of course — and the resulting production broke box-office records at the Duke of York’s in 2003. Friedman, who produced the Bean Macbeth , launched another big revival, Peter Nichols's A Day in the Death of Joe Egg , at the suggestion of its leading man, Clive Owen.

The impresario Nica Burns has also been guided by a star’s ambition. But she denies that it’s just about ego. “You work with an actor on something, and at some point they say: ‘Oh, I’ve always wanted to play X.’ And that’s fine, actually. They know what they are capable of. I’ve never had an actor miscast themselves.”

5. It’s time someone got Shakespeare right at last

The director Sam Mendes recently admitted that he chooses to revive plays because he feels he’s found their “secret”. And a director pursuing a vision, says Attenborough, can be a “perfectly honourable reason” for mounting a revival. “You’ve got to have a sense in your stomach that you know how to do it in a way nobody else has done before,” he says. “I felt that on a couple of occasions, in complete hubris, when I started at the RSC. When I did Romeo and Juliet, I thought, ‘Everyone’s got it wrong, I can do this right’.”

6. It’s time someone made sense of Chekhov

With foreign playwrights, it’s de rigueur to provide a new translation for any major revival. Often they’re by modern giants such as Christopher Hampton or David Hare. It helps to offer a unique selling point, and it nudges the play towards the present tense. “New versions can make pieces much more accessible,” says Rosemary Squire, the president of the Society of London Theatres. “Look at what Patrick Marber did to Moliãre in Don Juan in Soho. It honours the original, but it’s absolutely about today.”

7. You can’t get the parts these days

When we go to the theatre, we want to see great acting. And there’s a reason why great actors cling to great writers: they give them great parts. “Actors love doing Chekhov,” says Birmingham Rep’s artistic director, Rachel Kavanaugh, who’s about to stage Uncle Vanya. “He’s so nonjudgmental. He says, here are these people, what do you think about them? The characters are complicated, they’re never a mouthpiece for an idea.”

8. Someone has a bright idea

Why on earth did Sonia Friedman choose to bring Boeing Boeing, a silly 1960s sex farce, back into the West End? Because the director Matthew Warchus thought it would be funny. Friedman, who’d worked with Warchus on Beckett’s Endgame , “genuinely thought that he was joking at first”. But then she read it and fell for it. They agreed to go for the best possible cast, rather than the most famous possible cast, and hope that the reviews liked Mark Rylance and Roger Allam as much as they did. The result is a surprise hit that features one of the great comic turns of the decade from Rylance. “It’s worked,” says Friedman. “It’s really the definition of a revival: it’s brought something back from the dead.”

9. The writer mucks in

Why did Friedman revive Pinter’s The Dumb Waiter? Because Lee Evans wanted to do it? Because of its 50th anniversary? Because Pinter had been in the news thanks to turning 75, being seriously ill and winning a Nobel prize? These may all be factors in its success. “But the real reason it happened was because Harold wanted it done,” says Friedman. He helped the actors; he even took a bow on opening night. It doesn’t always work that way. The show’s co-producer Carole Winter tried to revive Brian Friel’s Dancing at Lughnasa, only to discover that Friel had banned all new productions: “Writers do fear overkill,” she says.

10. The time is ripe

A major revival mustn’t just make a nod to clumsy conflict in the Middle East ( The Entertainer ) or have someone big off the telly in it (Billie Piper in Treats ), it must lag long behind the last major revival. Equus hasn’t been seen since the 1970s. The Entertainer hasn’t been in the West End since 1986. In theatreland, as in everywhere else, scarcity brings value. “The really great plays have been done,” says Friedman, “so what you have to do is test how long the gap can be. When I did Noises Off , it had been only 13 or 14 years since the original production ended. People said it was too soon. But I said, ‘No, I would like to see it again’. Ultimately, you do just have to put on shows that you would like to see yourself.”

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