John Robinson

Infantry General at Field Briefing (uncredited)

Adm. Sir Bertram Ramsay (uncredited)

Jason Douglas / Sidney Fairweather

Pilot

Lord Fawnlee

Prof. Martineau / Mansel

Collings

Professor Bernard Quatermass

Berkeley Reckitt

Professor Gouin

Unnamed Character

Secretary

Muller / Muller (uncredited)

Sir Colenso Ridgeon

Archdeacon Pomphret

Old Ekdal

Dr. Braithwaite

Linnett

Dr. Bruce Napier

Lloyd Crichton / Detective Sergeant Leith

Charles de Bouvet / Reverend Roger Leyland

Hugh Turner

Dr Foster Hamilton

Thomas Northon / Dr. Larry Parker