Welcome to Versailles, the BBC’s steamy new period drama set in the court of Louis XIV

With scenes of sex, murder and conspiracy within the opening minutes of episode one, Versailles, a new 10-part television series that delves into the private lives of Louis XIV and his court, could never be described as "demure".

Add to the aforementioned raunchiness an unprecedented £24 million budget (twice as much as Downton Abbey) a cast full of Brits, a cavalier approach to historical fact, and a script shot in English, and the British may as well have invaded France and declared "guerre!"

"As soon as we started," says David Wolstencroft, co-creator of Versailles, "I said to my partner Simon Mirren: 'We're English and writing this in English. So with French patriotism and their general national pride — we are totally f——'!' But sometimes it takes a different context to shine a light on history."

Beginning in 1667 after the death of Louis' mother, Versailles tells the story of the Sun King's Machiavellian decision to move his court from Paris to Versailles, his father's former hunting lodge. At war with the nobility, the princes and the law courts, Louis (played by the British actor George Blagden) is determined to impose his will on his courtiers and reconcentrate power around the throne. He is also intent on having lots of sex with lots of women.

When the series, which was made by the broadcaster Canal+, premiered in France last November there were, perhaps not surprisingly, no complaints about the amount of sex, but an outcry over the decision to film a story about the most illustrious of all French monarchs in English.

"It is very worrying and totally implausible that a series about Louis XIV should be made in English," said Gaston Pellet, of the United Republican Group for Linguistic Resistance, Initiative and Emancipation. "We have nothing against English, but we don't want French to become a second language in France."

How, then, did two Brits come to be responsible for one of the most expensive and highest-rating French TV shows ever made?

"You need to have international sales to do a show this big, and we simply wouldn't have got them if the show had been made in French. More people in the world speak English, it's that simple," says Wolstencroft. One of Canal+'s customers was BBC Two, which is due to air the series next month.

Once Wolstencroft and Mirren (the nephew of Dame Helen) had been hired, the pair, who met on the hugely successful BBC show Spooks, decamped to France to start research in the Versailles archives.

Historical fact states that the life of Louis XIV was intensely, fantastically dramatic. The grandson of a Medici, he became king at the age of five, married the Spanish Infanta, almost had an affair with his brother's wife Henrietta, the sister of Charles II, and had so much sex and so many mistresses that his family tree became a tangled and confusing web of legitimate children, illegitimate children and "legitimised" children with certain mistresses.

"Sex was statecraft," says Wolstencroft. "The consummation of the marriage of Louis XIV and the Infanta of Spain, Maria Theresa, was dynastic geopolitics."

And Louis himself, as a psychological study, was a "black hole" according to Wolstencroft.

"So there was an opportunity to create this wonderful drama about the king and his desire to centralise power. We discovered that his brother Philippe was raised as a girl and dressed in women's clothes and effeminised so he wouldn't outshine his kingly brother.

"Suddenly we had a show about brothers, and that completely crystallised our viewpoint. We have a young king whose mother dies and the next year makes this massive decision to move the royal household — it would have been like moving the White House to Florida."

Alex Vlahos, the 28-year-old Welsh actor who plays Philippe, was awestruck at the scale of the job.

"My wig cost £4,000 and I had three — the set alone cost millions and the scale was massive, bigger than anything I had ever done," he says. "The sets were so lavish they had recreated the interior of the real Versailles down to the last centimetre."

The cast and crew are happy to admit there is a fair amount of poetic licence in Versailles. "We broke the rules," says Vlahos. "Sometimes in scenes we kick off our shoes — they would have never done that at the time. And my bedroom was always really messy — of course that would never have happened. But we chose to include these little nuances, however historically inaccurate, so the biggest possible audiences, including 18-year-olds in the UK, could relate to the lives of the young people we portray.

"We said when we were making it that this isn't a period drama, it's a show about young people in power, a 28-year-old king and his 26-year-old homosexual brother, young people who ruled the court, who introduced people to music and art and fashion, and threw the best house parties ever."

The truth wasn't always up for grabs. Mathieu de Vinha, scientific director of research at the Palace of Versailles, recalls many arguments with Wolstencroft and Mirren about the relevance of historical fact.

"I wrote a biography on Alexandre Bontemps, the first valet of the king who is very important in the show," he says. "At first they wanted to make him gay, but Bontemps was a good Catholic with a wife and four children and was absolutely not homosexual. If I'd accepted that all my work would have been destroyed — everyone would have said I couldn't do my job. So on that point I stood my ground!"

Yet Wolstencroft considers the mere notion of truth elusive and thus, in the end, unimportant. "When it comes to history there isn't one singular truth — we can't know, it's all speculation.

"We wanted it to be rock'n'roll. If you were in Versailles at that time you were at the centre of the world. You could lose a partner at midnight and be married at 9am to someone entirely different; from our point of view we get to tell those stories, but as someone who loves history and loves historiography, I'm not saying it's definitive."

He laughs. "And there's a massive twist at the end of the first episode you'll never believe happened for real, but it did. Real life is often better than fiction."