As The Globe's touring revival of Anne Boleyn, the veteran playwright's most recent original work, arrives in Edinburgh this week, his depiction of Henry VIII's second and most misunderstood wife is a deeply serious study of a woman whose apparent flirtation with then-outlawed Protestantism suggested a steely revolutionary zeal. By juxtaposing Anne's story with that of a wilfully outrageous James VI, himself in the throes of political intrigue even as he investigates Anne's legacy, the portrait that emerges of this most turbulent period of English and Scottish history is more audacious than most.
"I'd wanted to write something about the Tudors for years," says Brenton on a break from work on his next play, "but I couldn't find a way in. I had a mad idea to do something called Tudor Rose, and have one actress play all the monarchs, but I couldn't make it work. Then the Globe asked me to write something about the King James Bible, and I had this idea about James going off on a kind of ghost hunt to find out about Anne's past achievements, and something clicked. Plays come out of the woods in that way, where you try to get to the light.
"But the Tudors has become like a foundation story of England now.
"They're like an ancient Greece to us. All the stories of Bloody Mary and all the rest have become very potent and very powerful. On one level they're all about the founding of modern England, or they may go deeper than that. Anne Boleyn, for instance, has as huge fanbase among young women. People tend to see her as a sexual predator, and she may well have been that, but she was so much more. To become a secret Protestant was a very brave thing to do, and I began to see her as someone who was very courageous, and that surprised me."
The presence of James VI is particularly interesting for the play's only Scottish dates, and in many ways Brenton's play is as much his as it is Anne's. His portrayal, as an out-to-shock cross-dresser who at one point pulls on Anne's left-behind frock, looks more Rocky Horror than historical romp.
"James came from a very dangerous world," according to Brenton. "It was known that he had a very strange way of speaking, and he said some outrageous things that really shocked people. Some of the lines in the play are things that he actually said. He used this strange way of speaking to mask himself from others, but he was a very brilliant man.
"He was gay, and he was a modern man, and he realised that he must have a settlement, which later failed, of course, but there was something really disruptive about him, which is probably why I began to like him so much."
As one of the post 1968 cadre of English playwrights whose politically-based works went beyond fringe theatre to storm the barricades of the National Theatre and the Royal Shakespeare Company, Brenton has come a long way since making his professional stage debut at the Royal Court in 1966 with It's My Criminal. In 1968 Brenton joined the Brighton Combination collective as a writer and actor, then joined Portable Theatre, co-founded by David Hare, a year later.
It was throughout the 1970s when Brenton really found his stride, when, alongside peers including Hare, David Edgar, Trevor Griffiths, Snoo Wilson and others, he attempted to write epic state-of-the-nation plays from a leftist historical standpoint. The first of these, Magnificence, appeared in 1973, and told a still-pertinent tale of squat-dwelling terrorists and a Conservative MP. Brassneck, co-written with Hare, appeared the same year. The Churchill Play and Weapons of Happiness followed, while Epsom Downs was penned for Max Stafford Clark's Joint Stock company.
In 1980, The Romans in Britain appeared at the National Theatre. The play contrasted Julius Caesar's invasion of Celtic Britain with both the Saxon invasion of Roman-Celtic Britain and the then current British presence in Northern Ireland. It caused a storm when a scene of anal rape provoked a private prosecution by moral decency campaigner Mary Whitehouse. While the action failed, The Romans in Britain didn't receive a second production until 2006, while Brenton wasn't commissioned by the National Theatre again until 2005.
In between, Brenton collaborated with Hare again on the newspaper-based Pravda, co-wrote several pieces with another 1968 veteran, Tariq Ali, and, as with many of his fellow writers, found his leftist stance usurped in the 1990s. Politically, the triumphalism of a post-Berlin Wall age made the enemy harder to spot, while, theatrically, the so-called in-yer-face generation of writers captured the zeitgeist of uncertainty.
"I suppose you went in phases," Brenton says, curiously looking at himself in the second person. "In the 70s you were an attack dog during a time when you really felt there could've been a revolution in France, but didn't happen. The far left failed, and everything congealed, so this dream of open living was lost in a druggy nightmare. Then I became a more mainstream writer, when, while not an attack dog, you could still write these state of the nation plays. That went bust in 1989 and 1990, and then I went to Moscow, which was awful."
The 1990s, Brenton admits, "were very difficult. I went really out of fashion as this other bunch came along, and I only found my feet again about ten years ago, but on a broader plane, trying to understand the landscape."
In the early noughties, Brenton wrote thirteen episodes of Spooks, the spy-based TV drama with a quietly subversive up-to-the-minute agenda.
Then came Paul, about Paul the Apostle, and, for the Globe, In Extremis, a 12th-century epic that explored ideas of religion perhaps sired in Brenton's Methodist upbringing by his minister father.
Never So Good explored the life of Conservative Prime Minister Harold Macmillan, while a translation of Buchner's Danton's Death and an adaptation of Robert Tressell's The Ragged-Trousered Philanthropists appeared the same year as Anne Boleyn.
For all Brenton seems revitalised, any suggestion that today's climate of recession, a right-wing Government and the resulting wave of protest are a case of things moving full circle to something akin to the spirit of '68, isn't something Brenton agrees with.
"In the 1970s and 80s I did this huge amount of stuff in what I suppose was my heyday," Brenton says, "and back then the world felt clearer. It was going very much to the bad, Thatcher was in power, and I felt very much like an oppositional writer. What's happening now is that the capitalist system seems to be collapsing in Europe, but I don't know how serious it is. Is it over? Or is it just going to be this dreadful drizzly politics?"
Either way, Brenton observes that "People are getting back to attack-dog writing," even if he won't necessarily be joining in. "Your perspective changes," he insists, "but your opinions don't. I've worked out religion, now, I think. In my late sixties, after writing five plays on the trot set in the past, I've finally come to terms with the religious background that I left, so it's probably time to get back to writing about now. I'm almost 70, I have arthritis, and the NHS is falling to bits. I know a lot about that, so maybe I'll write about that next."
Anne Boleyn, Edinburgh Festival Theatre, today until May 12. www.fctt.org.uk