With fans still reeling from the climactic events of series three, the fourth series of BBC One's much loved drama Poldark begins filming this week.

Adapted by Debbie Horsfield from the novels by Winston Graham and produced by Mammoth Screen this eight part series, starring Aidan Turner as Ross Poldark and Eleanor Tomlinson as his wife Demelza, will film across Cornwall, the West Country and locations in London for transmission next year.

1796: Ross (Turner) must defend Cornwall from an empowered George Warleggan (Jack Farthing), and risks everything he holds dear as he embarks on a political journey which takes him to the nation's capital. Demelza (Tomlinson) finds her loyalties torn, 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.

Two powerful new characters enter the saga, as Rebecca Front (War And Peace, The Thick Of It) is Lady Whitworth, Ossie’s formidable mother, and Max Bennett (The Hollow Crown) is Monk Adderley, an unscrupulous society figure who is on a collision course with the Poldarks. Also back for series four are Harry Richardson and Tom York as Drake and Sam Carne, Beatie Edney as Prudie and Josh Whitehouse as Lieutenant Hugh Armitage, who remains deeply in love with Demelza.

Poldark has a strong returning audience averaging 6.7m consolidated viewers and a further 1m BBC iPlayer requests per episode across all three series.

Mammoth executive producer Karen Thrussell says: "We were hugely gratified by the massive amount of love the audience felt for series three. We hope this will be our strongest series yet, with eight brilliant scripts from Debbie Horsfield, a whole new world of stories and our very wonderful cast. In this series Ross and Demelza will face new challenges and try to turn their backs on old ghosts. Ross strives to become a better man, but his dark and reckless streak is never far from the surface and will lead to him facing new enemies and suffering great losses."

Elizabeth Kilgarriff, BBC Executive Producer, said: “The BBC One viewers adore Poldark and we can’t thank them enough for their continued support across the last three series. The hard work and dedication of the production team and cast is why the show just keeps getting better. Debbie’s scripts for series four are some of the best yet, and I can't wait to share what she has in store with the fans!”

Poldark is adapted by Debbie Horsfield (Age Before Beauty, Cutting It, The Riff Raff Element) produced by Michael Ray (Poldark) and directed by Joss Agnew (Mr Selfridge, Jekyll And Hyde) and Brian Kelly (The Loch, Outlander). Debbie Horsfield continues to serve as executive producer alongside Tom Mullens, Karen Thrussell and Damien Timmer for Mammoth Screen and Elizabeth Kilgarriff for the BBC.

Filming will take place across Cornwall and around Bristol, including the Bottle Yard Studios, over the coming months and the series will transmit in 2018 on BBC One.