A BritBox original, the six-part series “Outrageous” profiles the six Mitford sisters, sibling aristocrats without money whose colorful lives from the 1930s on won headlines and celebrity.

Nearly a century later, are we still fascinated?

“The fascination is,” theorized Bessie Carter who plays the eldest Mitford, Nancy, “that they were an unlikely group of women who were all in one family.

“How can that happen? How can one group of sisters, all raised under the same roof, end up all being so rebelliously unique and different?

“Also, our fascination with the past is because we want to try and learn how to be better in the present.”

They were indeed remarkable. Diana, the most glamorous and beautiful, married the Guinness brewery heir, had three children and then in a notorious scandal left her husband for Oswald Mosley, a notorious womanizer and fascist leader whose Black Shirts violently agitated for Nazi Germany as Britain prepared for war.

In 1936 Diana married Oswald in Berlin with Adolf Hitler present.

Carter, 31, finds Nancy a vivid contrast.

“Our story starts in 1931 and ends in 1938 just before the Second World War.

“It was really clever that our writer Sarah Williams made Nancy, the storyteller, the writer of the family, the narrator of the series.

“Nancy very much takes the audience’s hand with a cheeky wink to say, ‘Come with me. Let me tell you a story.’

“I voice over the series as well; we imagine that is Nancy years later, perhaps during or after the war. She has the power of hindsight to look back and know where this story leads.

“I don’t think she was the dominant one but she’s the one fighting to keep the family together.

“What the series asks of us is: Can you love a sibling but despise their politics? That’s the question we don’t try to answer. We try to pose that question to the audience.”

What is inescapable is the lowly status women held in these aristocratic households.

“Their father forbade any of the girls to be educated: ‘School’s for boys.’ Nancy went to school for about a term and then left — because she missed the comforts of a maid doing the laundry.”

The Mitford sisters educated themselves by reading every single book in the library of their estate.

“They had intelligence, energy, wit and intellect but were continually told, your only job is to get married and have a baby, which was still the main expectation of women at the time.

“Nancy was, luckily, always a writer. The other sisters didn’t really have that. Although actually, later on in life, they did all write books.”

BritBox streams the first two “Outrageous” episodes June 18