Lots of slogans such as "Be like Dad, Keep Mum" and "Keep it under your Hat" are visible on the walls in various scenes to reinforce the plot of this British wartime movie illustrating how gossipy talk can result in unknowingly giving valuable information to Nazi spies.
Mervyn Johns
as No 23: Mr Davis
Nova Pilbeam
as Beppie Leemans
Reginald Tate
as Maj. Richards
John Chandos
as No 16
Stephen Murray
as Mr. Barratt
Jack Hawkins
as Brigade Major Harcourt
Geoffrey Hibbert
as Pvt. John
Philip Friend
as Lt. Cummins
Phyllis Stanley
as Miss Clare
Mary Clare
as Mrs. Webster
Basil Sydney
as Naval captain
Joss Ambler
as Mr Vemon
