Benedict Cumberbatch

(Alan Turing)

Keira Knightley

(Joan Clarke)

Matthew Goode

(Hugh Alexander)

Rory Kinnear

(Detective Robert Nock)

Allen Leech

(John Cairncross)

Matthew Beard

(Peter Hilton)

Charles Dance

(Commander Denniston)

Mark Strong

(Stewart Menzies)

James Northcote

(Jack Good)

Tom Goodman-Hill

(Sergeant Staehl)

Steven Waddington

(Superintendent Smith)

Ilan Goodman

(Keith Furman)

Jack Tarlton

(Charles Richards)

Alex Lawther

(Young Alan Turing)

Jack Bannon

(Christopher Morcom)

Tuppence Middleton

(Helen)

James G. Nunn

(Sherborne Student 2)

David Charkham

(Joan's Father)

Victoria Wicks

(Joan's Mother)

Andrew Havill

(Teacher)

Tim van Eyken

(MI6 Agent)

Will Bowden

(Military Policeman)

Tim Steed

(Electrical Assistant)

Nicholas Blatt

(Ministry Man (uncredited))

Ancuta Breaban

(Wren (uncredited))

Grace Calder

(Assistant Wren (uncredited))

Daniel Chapple

(MI6 Agent (uncredited))

Alexander Cooper

(Bletchley Park Agent (uncredited))

Dennis Good

(Civilian (uncredited))

Debra Leigh-Taylor

(Evacuee (uncredited))

Stuart Matthews

(Bletchley Park Operative (uncredited))

David G. Robinson

(Police Sergeant White (uncredited))

Mark Underwood

(Crossword Man (uncredited))