Michael Gambon as Winston Churchill

Lindsay Duncan as Clemmie Churchill

Romola Garai as Millie Appleyard

Matthew Macfadyen as Randolph Churchill

Tara Fitzgerald as Diana Churchill

Rachael Stirling as Sarah Churchill

Bill Paterson as Lord Moran

Daisy Lewis as Mary Churchill

Alex Jennings as Anthony Eden

Chris Larkin as Rab Butler

James Wilby as Brendan Bracken

Patrick Kennedy as Jock Colville

Christian McKay as Christopher Soames

John Standing as Lord Camrose

Matilda Sturridge as Rosie Hopper

Matthew Marsh as Lord Beaverbrook

Ian Mercer as Sgt Murray

William Blenkinsop as Young Randolph

Eloise Webb as Young Diana

Dixie Egerickx as Young Sarah Churchill

Harper Gray as Young Nicholas Soames

Molly Ashby as Young Emma

Margot Orr as Marigold

Jon Wennington as Delegate (uncredited)