Poldark creator Debbie Horsfield has lifted the lid on the final season of the British period drama, which will air in 2019.

Horsfield has opened up about her approach to the fifth and final season of the Mammoth Screen-produced drama after BBC and PBS confirmed its end. This comes ahead of the launch of the fourth season, which launches on PBS Masterpiece on Sunday September 30 at 9pm.

Poldark is based on twelve novels by Winston Graham; season four is based on the seventh novel, The Angry Tide. However, the author left a gap of ten years before the eighth novel, The Stranger from the Sea.

Horsfield, who has written every episode of the four series, said, “In The Stranger from the Sea, Winston Graham made many references to developments that happened in the gap years. Much can also be inferred. There are, of course, also historical events and people of the time, both in Cornwall and in London. Series five will draw on all of these to follow the lives of the Poldarks, George Warleggan, the Enyses, and the Carnes in this intervening period.”

Aidan Turner and Eleanor Tomlinson will return as Ross and Demelza Poldark for the fifth series. Also back are Jack Farthing (George Warleggan), Luke Norris (Dr Dwight Enys), Gabriella Wilde (Caroline Enys), Ellise Chappell (Morwenna Carne), Harry Richardson (Drake Carne), Tom York as Sam Carne, and Beatie Edney as Prudie.

The fifth season starts in a new century and with this comes the promise of a hopeful future, but the past casts a long shadow over Cornwall. Ross Poldark resolves to put Westminster behind him and spend more time with the people he loves. However, when an old friend emerges with a plea for help, Ross is compelled to challenge the establishment again. As the Enyses (Luke Norris and Gabriella Wilde) rally to join the cause, Demelza (Eleanor Tomlinson) must contend with dangers close to home, while George (Jack Farthing) courts corrupt powers whose influence spans the Empire.

Karen Thrussell, executive producer for Mammoth, said, “At Mammoth we’re all fans of the Poldark books and we hope our audience will continue with us on the next stage of the journey. We are confident that fans of the novels will appreciate the care with which Debbie Horsfield is continuing to adapt Winston Graham’s saga. This will be the last series in the Poldark chronicle… for now. Who knows what the future may bring.”

A number of new cast members are joining Poldark for series five, including Lily Dodsworth Evans (Genius), Kerri McLean (Electric Dreams) and Sofia Oxenham (Grantchester), Vincent Regan (300), Peter Sullivan (Entebbe) and Freddie Wise (Maleficent 2).

Andrew Graham, son of Poldark author Winston Graham and series consultant on behalf of the Winston Graham Estate, added: “No-one can know what my father would have felt about the forthcoming series, let alone what he might have written. However, Debbie Horsfield has demonstrated such an extraordinary affinity with his work and shown such remarkable skill in bringing his Poldark characters to the screen that we know we are in safe hands. Indeed, without her, the Estate would not have agreed to series five in this form.”

Filming has already started on the fifth season and will air in 2019.