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

Dominic Charman

Sherborne Student 1

James G. Nunn

Sherborne Student 2

Charlie Manton

Sherborne Student 3

David Charkham

Joan's Father

Victoria Wicks

Joan's Mother

Andrew Havill

Teacher

Laurence Kennedy

Headmaster

Tim van Eyken

MI6 Agent

Will Bowden

Military Policeman

Miranda Bell

Margaret

Tim Steed

Electrical Assistant

Hayley Joanne Bacon

Woman in Crowd (uncredited)

Nicholas Blatt

Ministry Man (uncredited)

Ancuta Breaban

Wren (uncredited)

Alex Corbet Burcher

Dancer (uncredited)

Grace Calder

Assistant Wren (uncredited)

Richard Campbell

Crossword Man in Pub (uncredited)

Daniel Chapple

MI6 Agent (uncredited)

Lisa Colquhoun

Joan Clarke's Friend (uncredited)

Alexander Cooper

Bletchley Park Agent (uncredited)

Leigh Dent

Passerby (uncredited)

Sam Exley

Military Policeman 3 (uncredited)

Dennis Good

Civilian (uncredited)

Debra Leigh-Taylor

Evacuee (uncredited)

Stuart Matthews

Bletchley Park Operative (uncredited)

Joseph Oliveira

MI6 Agent (uncredited)

Mark Underwood

Crossword Man (uncredited)

Joshua Wichard

German Spy Plane Pilot (uncredited)