Helen McCrory will play a Tory prime minister "hanging on to power" in a new TV show.

Helen McCrory

Helen McCrory

The 51-year-old actress has been cast as fictional politician Dawn Ellison in David Hare's upcoming BBC One drama 'Roadkill', with Hugh Laurie, 60, already announced as minister Peter Laurence, who is also fighting for his career.

Speaking to the Daily Mail newspaper columnist Baz Bamigboye, writer David confirmed Helen's casting and insisted she isn't based on former Conservative female PMs Theresa May or Margaret Thatcher.

He said: "Unfortunately, we're so short on role models of a woman prime minister that people will think its one of the two.

"But I promise you it's neither."

The four-part political thriller looks at "the future of the Conservative party but after Brexit".

David, 72, is keen to distance his show from any connections to modern politics, as he insisted there is no influence from "real people".

He stressed: "[It is] not remotely about [current Prime Minister] Boris Johnson, Theresa May or Brexit. It is not in any way based on real people."

But the 'Plenty' playwright revealed his inspiration does come from how the political landscape has changed in the modern world, as he pointed to behaviour by both Johnson and US president Donald Trump.

He said: "['Roadkill' is] really about shamelessness, and how the rules in the 21st century have changed.

"It used to be that when you committed a 'crime', there was something called disgrace.

"But no longer ... we can see that in politics throughout the world."

Helen and Hugh will be joined in the cast by Ophelia Lovibond and Millie Brady - as the latter's on-screen daughters - while Sarah Greene will play an investigative journalist.

Pippa Bennett-Warner will portray a lawyer, and Patricia Hodge has been approached for the role of the proprietor of a newspaper.

Rounding off the cast are the likes of Olivia Vinall, Iain De Caestecker, Katie Leung, Danny Ashok, Pip Torrens and Shalom Brune-Franklin.