Richard Todd as Wing Commander Guy Gibson, V.C., D.S.O., D.F.C.

Michael Redgrave as Doctor B. N. Wallis, C.B.E., F.R.S.

Ursula Jeans as Mrs. Wallis

Basil Sydney as Air Chief Marshal Sir Arthur Harris G.C.B., O.B.E., A.F.C.

Patrick Barr as Captain Joseph (Mutt) Summers, C.B.E.

Ernest Clark as Air Vice-Marshal The Hon. Ralph Cochrane G.B.E., K.C.B., A.F.C.

Derek Farr as Group Captain J. N. H. Whitworth, D.S.O., D.F.C.

Charles Carson as Doctor

Stanley Van Beers as Sir David Pye, C.B., F.R.S.

Colin Tapley as Doctor W.H. Glanville, C.B., C.B.E.

Frederick Leister as Committee Member

Eric Messiter as Committee Member

Laidman Browne as Committee Member

Raymond Huntley as Official, National Physical Laboratory

Hugh Manning as Official, Ministry of Aircraft Production

Edwin Styles as Observer at Trials

Hugh Moxey as Observer at Trials

Anthony Shaw as R.A.F. Officer at Trials

Laurence Naismith as Farmer

Harold Siddons as Group Signals Officer

Frank Phillips as BBC Announcer

Brewster Mason as Flt / Lt. R. D. Trevor-Roper, D.F.C., D.F.M.

Tony Doonan as Flt / Lt. R. E. G. Hutchison, D.F.C.

Nigel Stock as Flying / Off. F. M. Spafford, D.F.C., D.F.M.

Brian Nissen as Flt / Lt. A. T. Taerum, D.F.C.

Robert Shaw as Flt / Sgt. J. Pulford, D.F.M.

Peter Assinder as Plt/Off. G. A. Deering, D.F.C.

Richard Leech as Squadron Leader H. M. Young, D.F.C.

Richard Thorp as Squadron Leader H. E. Maudslay, D.F.C.

John Fraser as Flight Lieutenant J. V. Hopgood, D.F.C.

David Morell as Flight Lieutenant W. Astell, D.F.C.

Bill Kerr as Flight Lieutenant H. B. Martin, D.S.O., D.F.C., A.F.C.

George Baker as Flight Lieutenant D. J. H. Maltby, D.S.O., D.F.C.

Ronald Wilson as Flight Lieutenant D. J. Shannon, D.S.O., D.F.C.

Denys Graham as Flying Officer L. G. Knight, D.S.O.

Basil Appleby as Flight Lieutenant R. C. Hay, D.F.C.

Tim Turner as Flight Lieutenant J. F. Leggo, D.F.C.

Ewen Solon as Flight Sergeant G. E. Powell

Harold Goodwin as Wing Comdr. Gibson's Batman

Patrick McGoohan as Guard at door (uncredited)

Peter Arne as Staff Officer to Air-Vice Marshal Cochrane (uncredited)

Edward Cast as Crew Member (uncredited)

Richard Coleman as RAF Officer (uncredited)

Peter Diamond as Tail Gunner (uncredited)

Gerald Harper as RAF Officer (uncredited)

Arthur Howard as RAF Pay Clerk in NAAFI (uncredited)

Lloyd Lamble as Collins (uncredited)

Philip Latham as Flight Sergeant (uncredited)

Edwin Richfield as RAF Officer (uncredited)