You may not know all their names – there are six of them after all – but if you have even a passing interest in 1930s Britain, you’ll have heard of the Mitford sisters.

The gaggle of rather scandalous, high-society siblings – Nancy, Pamela, Diana, Unity, Jessica and Deborah – tore up the aristocratic social scene of their day, making headlines, partying to excess, and rubbing shoulders with the rich and politically well connected (they were family friends with Winston Churchill), as well as the politically extreme.

'They are a fascinating family,' says James Purefoy, 61, best known for playing Marcus Antonius in the HBO series Rome, who appears as the family’s patriarch, Farve, in the period drama Outrageous.

James says he knows 'probably more than most, but not as much as an expert' when it comes to the sisters, and their lone brother Tom.

The Taunton-born actor actually knows a descendant of Diana, who famously married Oswald Mosley, leader of the British Union of Fascists, and hosted Adolf Hitler as a guest of honour at their wedding. Unity was similarly notorious for being chums with the Nazi leader.

The show has been created and written by Sarah Williams (Small Island, Flesh and Blood, Becoming Jane) and is based on the biography, The Mitford Girls by Mary Lovell, which tells the story of these raucous, uncompromising and yes, outrageous, women, during the decade leading up to the outbreak of the Second World War.

'Farve comes from a different time. He fought in the First World War. He lost a lung. He obviously didn’t see that’s too much of a problem,' says James, who stars alongside Four Weddings and a Funeral legend, Anna Chancellor, 60, playing Muv, the girls’ mother. 'He’s also got these six girls who are incredibly opinionated, when he comes from a generation where women didn’t have opinions or votes, and were seen as very much as chattels.

'He simply cannot conceive of what these girls are doing with opinions. Why would they want to go to school? Why would they want to go to university? Because for eons, for generations, they just didn’t do that. It makes no sense to him at all. So he’s in a constant state of astonishment as to, why? What the hell? How did this happen?'

'He comes from a different time. He fought in the First World War. He lost a lung. He obviously didn't see that's too much of a problem,' says Purefoy of Farve.'He comes from a different time. He fought in the First World War. He lost a lung. He obviously didn't see that's too much of a problem,' says Purefoy of Farve. Bridgerton actress Bessie Carter, 31, plays Nancy, the eldest Mitford sister, Isobel Jesper Jones (The Hunger Games: The Ballad of Songbirds & Snakes) is Pamela, Scottish actor Joanna Vanderham, 34, stars as Diana, Shannon Watson (Say Nothing) as Unity, theatre actress Zoe Brough, 22, plays Jessica and Orla Hill (Swallows And Amazons) appears as Deborah, the youngest Mitford sister.

'They all do really beautiful, beautiful jobs. They’re utter individuals, but you completely see that they’re a family and they’re all part of the same unit, and they all go in these crazy, mad, different ways,' says James of his on-screen progeny.

In real life he is a dad of four and actually left school originally with just one O-level himself, and says there are 'soft sides' to Farve. 'He does care very deeply about his children.' The thing is, though, he adds: 'We all have trouble with our kids, but not all of our kids are hanging out with Adolf Hitler.'

And this is what gives Outrageous its bite, because amidst the glitzy period costumes, artful hair (James grew a 'massive' moustache for it: 'I think there was a small family living in it, perhaps mice'), champagne and decadent schmoozing, the series is also very much 'a word of warning across the generations.'

'We have such a polarised world. There are people I don’t speak to now because of their politics; that didn’t happen years and years ago,' says James passionately. 'My father was a Conservative, he worked for the Tory party, I was a young radical actor, and we would have long, interesting discussions about it, but it didn’t break people apart.

'Now it stops people talking for years. Brexit was a massive break in a lot of people’s lives with other people. The rise of Trump and Farage, it’s exactly the same thing,' he continues.

'It’s like a massive concrete block thrown into the pond of familial relationships, which have wide ranging ripples that go on for a long time.'

He argues that this is what good drama is for, making us reflect on those ripples and nudging us to ask ourselves, 'What are we facing? Do we recognise this world? Yes, we do. Things haven’t changed. The whole idea of ‘never forget’ seems to have disappeared somewhere,' muses James.

'This show helps us step back a little bit, look at it, and go, ‘Where are we now? Really, we shouldn’t be going down this road’. We need to converse and we need to persuade and talk and try to find middle ground so that we can get on again.'

This year marks James' 40th as a professional actor, a career that spans A Discovery of Witches, A Knight’s Tale, numerous stage productions and even a screen test for James Bond (he was pipped at the post by Pierce Brosnan), and he says you can see why some shows you’re in get cancelled, 'other stuff, you go, ‘you’d be crazy to cancel’. And this is one of those.'

Not only is Outrageous a tantalising, extraordinary story, but is one 'told with such contemporary energy and spice, vim and vigor' that you can’t miss it, promises James. 'It’s an easy watch, but it does leave you alarmed at what we’re all capable of, especially given that we have the hindsight, and they didn’t.'

Outrageous can be viewed via Sky and Google Play on U and U&DRAMA

Pull QUOTE ' Amidst the glitzy period costumes, artful hair, champagne and decadent schmoozing, the series is also very much 'a word of warning across the generations.'