Helen McCrory will play the prime minister in a new political thriller on BBC One.

The Peaky Blinders star will play PM Dawn Ellison in Roadkill, a four-part fictional series written by Sir David Hare, which “explores the relationship between personal morality and political power”.

McCrory is joining previously confirmed cast member Hugh Laurie, who will play a “charismatic” Conservative minister.

Hugh Laurie
Hugh Laurie (Ian West/PA)

The cast will also include Saskia Reeves (Us, The Child In Time) Sarah Greene (Dublin Murders, Normal People), Patricia Hodge (A Very English Scandal, Miranda) and Ophelia Lovibond (WIA).

McCrory, 51, is known for her role as Polly Gray, the aunt of Cillian Murphy’s character Tommy Shelby, in hit drama Peaky Blinders, and she also recently appeared in BBC Two drama MotherFatherSon opposite Richard Gere.

She has appeared in the Harry Potter films, Skyfall, The Queen and TV series Penny Dreadful.

Screenwriter and playwright Sir David, known for the films Collateral, The Reader and The Hours, said: “The casting of Roadkill illustrates the extraordinary depth and range newly on show in British film acting. Hugh Laurie is leading a great ensemble.”

Laurie will play Peter Laurence, a self-made, forceful and charismatic Tory MP whose public and private lives appear to be falling apart at the hands of his enemies.

As the personal revelations spiral, Peter is shamelessly untroubled by guilt or remorse, skilfully walking the thin line between glory and catastrophe as he looks to further his own agenda while others plot to bring him down.

But it becomes apparent how difficult it is, for both an individual and a country, to leave the past behind, and Peter must attempt to outrun his own secrets to win the ultimate prize.

Roadkill is a co-production between BBC One and Masterpiece on PBS in the US.