Will Hay as Prof. Davis

John Mills as Bobby Jessop

Basil Sydney as Costello

Felix Aylmer as Crabtree

Thora Hird as Joyce

Henry Hewitt as Prof. Davys

Owen Reynolds as Harman

Frank Cellier as Innsbach

Joss Ambler as Sir John

Frank Allenby as Onslowe

Margaret Halstan as Matron

Barbara Valerie as Sister Spooner

Leslie Mitchell as B.B.C. Interviewer

George Woodbridge as Male Nurse

George Merritt as Station Master

Aubrey Mallalieu as Ticket Collector

Diana Beaumont as Sister at Nursing Home

John Boxer as Hotel Receptionist

Cyril Chamberlain as B.B.C. Producer

Richard George as Hospital Nurse

Kenneth Griffith as Butcher's Boy

Dorothy Hamilton as Miss Rudge

Roddy Hughes as Journalist

Katie Johnson as Train Passenger

Agnes Lauchlan as Mrs. Webster

Brefni O'Rorke as Ministry Receptionist

Marjorie Rhodes as Nurse

Ronald Shiner as Porter