The origin and inspiration for The Devil's Whore.

At the beginning of every production is the idea. The idea for this one originated with Martine Brant, the co-writer of The Devil's Whore, who came up with the concept for the drama 14 years ago. It was inspired by her academic work and also in part by her historic Oxford home.

"I have always been intrigued by women who break the mould, who don't conform, who make their voices heard. I wrote my thesis on the gallows speeches of women in the 17th century hanged at Tyburn, often for petty offences - most of them pitifully misunderstood and persecuted for not conforming to a patriarchal system. I live in a 16th century house just outside Oxford where Cromwell stayed during the siege of Oxford. I became fascinated by the idea of a nobly-born woman in the Civil War who stepped outside the conventions of her estate and found her own voice amidst the chaos and convulsions of the English revolution."

"Why the Civil War? Because today we have a collective amnesia about these transformational years in which our basic liberties were won - the sovereignty of Parliament, freedom from arbitrary arrest and detention, religious toleration... in short, freedom from tyranny. Today we watch each one of these precious, hard-won liberties being systematically eroded."

With such a resonant political story to tell, it was an inspired decision by Channel 4's Controller of Film and Drama, Tessa Ross, to put Brant together with Peter Flannery. Brant hugely admired Flannery's work, especially his ground-breaking drama, Blind Justice. It was an immediate meeting of minds. "We wanted the drama to ask the big questions of justice, freedom and equality as well as being a compelling tale of love and adventure."

Executive Producer George Faber at Company Pictures was immediately hooked. "It is one of the great untold stories of British history. This was the original revolution that inspired both the American War of Independence and the French Revolution. Yet it had been significantly ignored, omitted and marginalised in dramatic terms."

Marc Munden, the director, was also struck by how modern it felt for such a historic piece. "It's a very contemporary political story, but it's wrapped up in 17th-century history. It's a mixture of adventure, a love story, real history and politics and the opportunity to tell the story about a failed republicanism."

Channel 4 may not be known for period drama but Channel 4 Head of Drama Liza Marshall argues: "It still feels quintessentially Channel 4 to me, because it's about radical politics. It's fresh and original and distinctive, all of the things we try and do with our drama. It's also a real privilege to have Peter Flannery's next great passion piece (after Our Friends in the North)."

As with any drama, particularly a historical one, the next question was where to film. The answer was a surprising one. "We discovered that within 50km of Cape Town we had the landscape and even some buildings that were a great match for southern England. We would never have got the same value if we'd filmed in the UK," says Faber.

"Once we'd found the landscape which looked like England, we were on our way," says Production Designer Rob Harris. "We built Fanshawe House, which was a really central part of the production, in a valley called Oak Valley. One of the original English settlers there had planted acre upon acre of English oak trees. It was a good place to do it."

"Even in England we'd have had to build most of the sets for both exteriors and interiors, because obviously from that period they either don't exist or have been changed greatly or they're scattered all over the country."

Not that the building of such ambitious sets was without difficulties. "The sheer scale of building the interiors of palaces, prisons, corridors, Elizabethan country houses, was a real challenge," says Faber. "The detail and the finish had to be convincing enough for the audience to be unaware of any of the artifice."

Equally Michele Clapton, the costume designer, worked closely with each cast member making their period dress. "It was wonderful to be able to literally start from scratch on 80 per cent of the costumes. To recreate 17th-century English costumes was a daunting prospect, from court costumes through to military gear."

For Brant and Flannery, it's the culmination of years of work, on a project that has become very personal. It turns out that it's not just Brant's house that is an inspiration. "My husband's ancestry through his mother goes back to the Fanshawes. They were courtiers to Charles I. My three daughters are direct descendents of Lady Ann Fanshawe, who met her husband, Sir Richard Fanshawe, at Charles I's court at Christ Church, Oxford. She published her memoirs, which have been a really valuable resource. The character of Angelica draws on Ann Fanshawe's legacy, and I hope her courageous and passionate story will be an inspiration to my own girls."