Room for one more at the keyboard?

From 'Decade' to 'Sixty-Six Books', co-authored drama is all the rage. Holly Williams talks to playwrights about collaboration and conflict

'Inevitably, it will be tapas rather than a single meal." So says Rupert Goold, artistic director of theatre company Headlong, of its latest project, Decade – not a play about 10 years of eating Spanish food, but a serious, ambitious beast exploring our reaction to 9/11 as we approach its 10th anniversary.

That tapas comparison is apt because this production takes an innovative approach to authorship: Headlong has asked several writers to contribute short scenes or mini-plays – a "mosaic of responses".

Despite theatre often being trumpeted as the most collaborative of artforms, when it comes to authorship we seem rather in thrall to the idea of the individual writer. And while we're used a TV show or film with a bunch of writing credits, we expect theatre programmes to boast a single name. Goold himself insists he was sceptical about plays with multiple authors – before he started to work on a 9/11 project. "It is such a huge, complicated subject. [People would] always say, 'You've got to have a Muslim voice, an American voice, a London voice...'. And people always disagree about it – its significance, its impact. It has a Babel-like quality."

The production will reflect this; the list of contributing authors so far includes Mike Bartlett, Abi Morgan and Alecky Blythe. Bartlett echoes Goold, suggesting "you've got to have a really good reason to have lots of writers and voices on a project – and if ever there was a good subject for lots of different points of view, it's 9/11. It affected everyone in some way."

Goold is not the only director using multiple voices to deal with a big topic this autumn. Sixty-six writers are involved with the Bush Theatre's celebration of the 400th anniversary of the King James Bible, from Carol Ann Duffy to the Archbishop of Canterbury, Billy Bragg and Wole Soyinka. Sixty-Six Books is curated by the Bush's artistic director, Josie Rourke: "It's a celebration of one of the great works in the English language – the King James Bible, which is a co-authored work itself: one of the greatest things ever written by committee, as they say."

Sixty-Six Books is perhaps more polyphonic performance cycle than co-authored play. "We didn't sit in a room writing together, with Billy Bragg and the Archbishop of Canterbury – though that would be ridiculously fun," says Jack Thorne, who has penned a response to the Book of Daniel. He was also one of four writers on the National Theatre's climate-change drama Greenland, in February. He, Moira Buffini, Matt Charman and Penelope Skinner wrote separately; their sections were intertwined by director Bijan Sheibani and dramaturg Ben Power. Climate change is a subject so big that multiple perspectives was surely a sound idea, even if, as Thorne posits, the show "didn't totally work". "By the end," he says, "we were able to talk very honestly – if we hadn't been so scared of it earlier, that would have helped the play. We were slightly too wary of people's egos."

A rare recent example of critically acclaimed co-authorship is the 2010 play A Thousand Stars Explode in the Sky, by Robert Holman, Simon Stephens and David Eldridge. Although the play deals with the end of the world, they approached it through the microcosm of one family. "We like the way a galactic event refracted the smallness of what it is to be a human," says Stephens.

Holman explains that they wanted to avoid following in the footsteps of Howard Brenton and David Hare, whose collaborations in the Seventies and Eighties, such as Labour Party drama Brassneck, or Pravda (about a Murdoch-esque media baron – surely due a revival), were political, issue-led, public plays. Instead, they began by daring each other to write the most personal scene they'd ever produced. There followed years of writing together and editing each other's work. But Holman insists it "wasn't a love-in", and it was quite tough if someone said: "That's rubbish."

Holman was something of a hero, and certainly an influence on Stephens and Eldridge; by the end, he was a friend too. And their solution for making sure egos didn't get the better of the play? Going to the pub.

Stephens recalls that "by the time we started rehearsals, no one could recall who had written which bits – all 30 fingerprints were on every page." But how do you create a unity of narrative, structure, tone? How do you use the voices of many without it becoming a cacophony?

This was a problem facing RSC director Gregory Doran when he decided to stage Cardenio this summer. It's got, as he puts it, "more writers than a Hollywood blockbuster". His script uses Double Falsehood, an 18th-century adaptation of a lost collaboration between Shakespeare and John Fletcher, which itself was based on – and here supplemented by – a translation of Cervantes' Don Quixote by Thomas Shelton, along with snippets from other Fletcher plays. Nonetheless, Doran's ultimate aim was "a sense of consistency ... you have to think of the final piece as the most important thing".

Shakespeare also worked with Fletcher on Henry VIII and The Two Noble Kinsmen, and with other writers on Titus Andronicus, Timon of Athens and Pericles. Despite an academic tradition that has been resistant to the notion of Shakespeare as anything other than a solitary genius, it should come as no real surprise: Elizabethan and Jacobean playwrights loved to collaborate. It is thought as many as half of the plays put on between 1590 and 1642 were the work of more than one hand. As Professor Sir Brian Vickers writes in Shakespeare, Co-Author: "Given that ... every major and most minor dramatists shared in the writing of plays, it would have been highly unusual if Shakespeare had not...".

Vickers explains: "Collaboration was a normal way of sharing the burden of composition, producing a script more quickly." While Doran suggests that, with 30 or 40 shows on in one season, "it was like writing for telly, for soap operas", although he is quick to point out that collaborations could also be artistically beneficial. Likewise, Vickers concludes "some extant masterpieces were produced by two or more co-authors".

Today we tend to prize the single authorial voice. Yet whether it's because a topic is too big, or because writing with another can be inspiring and challenging, sometimes one voice isn't enough. It might just be time to tuck into some theatrical tapas.

'Decade' (020-7452 3000) to 15 Oct; 'Sixty-Six Books' (020-8743 5050) to 29 Oct; 'Cardenio' (0844 800 1110) to 6 Oct