Poldark star Aidan Turner has said he expects the hit BBC drama to come to an end next year.

The actor’s portrayal of Ross Poldark will be back on screens next month as the show returns for a fourth series.

And while a fifth series for 2019 has been commissioned, Turner believes that will be the “last one” for the foreseeable future.

He said he had “mixed feelings” about the drama – based on the historical novels of Winston Graham – coming to an end.

Graham’s 12 books, published from 1945 to 1953 and continued from 1973 to 2002, are split between the 18th and 19th centuries and Turner said he could return to deal with the character’s later years one day.

“It’s been big for us all and it’ll always be a special thing but things naturally do come to an end and I think we’ve done really well with Winston’s books and I hope he’d be really proud,” Turner said.

“But it’s nice when things naturally come to an end, you don’t want things to go on really long.”

He added: “I think next year might be the last one, certainly for a while.

“We may come back, who knows. There’s a huge gap in the books, about 15 years.

“I wouldn’t age up, I’d come back in 10 years. I’d revisit it the right way, I’m not putting grey in my hair or anything like that.”

Set in 1796, the fourth series will see Poldark trying to defend Cornwall from an empowered George Warleggan (Jack Farthing), and risking everything as he embarks on a political journey which takes him to the capital.

His wife Demelza, played by Eleanor Tomlinson, finds her loyalties torn, as Elizabeth (Heida Reed) tries to strengthen her marriage, Morwenna (Ellise Chappell) continues to be oppressed by husband Reverend Ossie Whitworth (Christian Brassington), and the Enyses (Luke Norris and Gabriella Wilde) are tested as never before.