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The drama focuses on Churchill's period in the political wilderness before the war when his warnings about the rise of the Nazis were ignored.

"The story revolves around his beloved home, Chartwell, which was his refuge during these difficult time," said a BBC spokesperson.

Derek Jacobi is to play then Prime Minister Stanley Baldwin, with whom Churchill clashed over independence for India.

Other cast-members include Jim Broadbent as Churchill's friend Desmond Morton, Ronnie Barker as Churchill's manservant, Hugh Bonneville as Ivo Pettifer and Celia Imrie as Churchill's secretary.

First elected

The film is also executive produced by Ridley Scott's brother, Top Gun director Tony.

The director will be Richard Loncraine who worked on Band of Brothers.

Churchill was first elected to Parliament as a Conservative in 1900, though he crossed the floor, becoming a Liberal, in 1904.

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By the time World War I broke out he was already a national figure and First Lord of the Admiralty.

However a disastrous outing at Gallipoli cost him his job, though he stayed in active service to the end of the war.

During the 1920s he returned to the Conservative party, before falling from political power during the 1930s.

Redgrave is to play Clementine Hozier, granddaughter of the 10th Earl of Airlie, who Churchill married in 1908.

The pair had a long happy marriage and five children, four of whom survived into adulthood.

The action of A Lonely War will centre on the Churchill's home Chartwell and is to explore his personal life as well as his political battles.

The shoot is about to begin at Shepperton studios and on location.

A Lonely War will be broadcast on BBC television next year.