Rather than a faithful adaptation of Winston Graham’s Poldark novels – set 200 years ago – the fifth and final season is an original story from screenwriter Debbie Horsfield, approved by the Graham estate.
The six-parter features two real-life characters, including Irish-born Colonel Ned Despard, played by Vincent Regan, who married a freed black slave.
He administered the British dependency of Honduras and in 1790 wed Kitty (actress Kerri McLean). The couple went on to campaign for an end to enslavement.
Ned’s impetuous traits are very similar to Ross Poldark’s, said Regan. “Ned’s story fits incredibly well into that world. Playing him was interesting and the fact he had a real, poignant story gave him gravitas.
“His was a mixed-race marriage 200 years ago which is quite extraordinary. Kitty is very strong; a hugely brave woman.”
In an interview in this week’s S Mag, McLean revealed: “Kitty and Ned were probably the only middle-class, mixed-raced couple married in the UK.”
Elsewhere, fans will discover new feelings for baddie George Warleggan. He is still reeling after the death of wife Elizabeth so seeks out “therapy” – again unheard of – from Dwight Enys, physician to Poldark (Aidan Turner).
Actor Jack Farthing, who plays George, said: “The most challenging work I’ve done in the past five years is all in this series. George is grieving in a particular and dramatic way.
“There are climaxes to his sadness and some of them were pretty challenging to film.
“There are moments where Dwight (Luke Norris) takes him on as a patient and, in a modern and intelligent way, goes through talking therapy with him.
“Dwight realises he needs to talk to George and make him confront his grief rather than allow him to continue to evade it.”
It means Warleggan is less intent on bringing down his nemesis, Poldark.
Farthing said: “People have George labelled as a ‘baddie’ so it is interesting when you find yourself feeling sorry for him or momentarily sad for him.”
● Poldark, BBC One, tonight at 9pm.