Rosamund Welchman
Herself - Gordon Welchman's Daughter

W. Gordon Welchman
Himself - Ex-Head of Hut 6, Bletchley Park (1939-1941) (archive footage)

Sinclair McKay
Himself - Author, 'The Secret Life of Bletchley Park'

Jimmy Thirsk
Himself - Veteran, Hut 6

Asa Briggs
Himself - Veteran, Hut 6

Jane Fawcett
Herself - Veteran, Hut 6

Tony Comer
Himself - GCHQ Historian and Former Analyst

John Naughton
Himself - Vice President, Wolfson College, Cambridge (as Prof John Naughton)

John Scarlett
Himself - Chairman, Bletchley Park Trust, and Former Chief, MI6 (as Sir John Scarlett KCMG OBE)

Jennifer Welchman
Herself - Gordon Welchman's Granddaughter

Robert R. Everett
Himself - Former President, The MITRE Corporation

Eric Ellingson
Himself - Gordon Welchman's Colleague

Larry Hill
Himself - Gordon Welchman's Colleague