Callum Turner as Bill Rohan

Caleb Landry Jones as Percy Hapgood

Pat Shortt as Redmond

David Thewlis as Sargeant Major Bradley

Richard E. Grant as Major Cross

Tamsin Egerton as Ophelia

Vanessa Kirby as Dawn Rohan

Aimee-Ffion Edwards as Sophie Adams

Brían F. O'Byrne as RSM Digby

Sinéad Cusack as Grace Rohan

David Hayman as Clive Rohan

John Standing as Grandfather George

Simon Paisley Day as MI-5 Man 1

Julian Wadham as Colonel Fielding

Tom Stuart as Lt. Fortesque Brown

Alfie Stewart as Private Henderson

Sebastian Rice-Edwards as Young Bill

Jonah Russell as Dr. Smythe