Reginald Tate

as King Peter

as Professor Bernard Quatermass (6 episodes)

as Vice Adm. Payne

as Leblanc

as Colonel Wilkes

as Hugh Fitzooth

as Inspector Eliot

as the editor

as Austin Ruthyn

as Trevor Mangin

as Commanding Officer, Initial Training Wing

as Ricardi

as Dr Charles Ackroyd

as The Training Company Commanding Officer

as van Zijl

as Maj. Richards

as Ackroyd

as Rev. John Rider

as Mate of Q-Boat

as Chester

as Allan Hayden

as Tom Evans

as Hubert Perrin