He likened Churchill to great Shakespearean characters such as King Lear, a role he played to acclaim at the National Theatre.
The film will also bring out the role played by his wife Clementine in saving him from physical and mental collapse and inspiring him to greatness.
He spent nine months “listening – morning, afternoon and evening – to 24 double-sided LPs of all the speeches he’d made.”
The film, Churchill, shot in Scotland, focuses on the run-up to D-day in summer 1944, portraying the prime minister as a man fearful of history repeating itself.