When watching this film, I think it imperative that you cast your mind (or imagination) back to just how precarious things were in Britain in 1942. The pack-hunting U-boat tactics operational in the Atlantic were proving effective for the Nazis, and causing significant shortages. It is against that backdrop that the usually jocular Will Hay takes on the more serious role of a Royal Navy Captain working on a blockade of supplies reaching the Reich. Ably assisted by Bernard Miles and a cast of thousands including John Mills, Leslie Banks, Michael Rennie and their on-screen counterparts Albert Lieven, Marius Goring and a curiously cast Robert Morley, they keep it moving, rather dryly, for 70-odd minutes. It is not a very good piece of cinema, indeed it may well have come from the Army Cinematograph Unit by the looks of it - but it served a purpose, and that ought not to be underestimated as it rolls along.