A burglar Frank Murray breaks into the office safe of Maple Photograpy for the petty cash but finds a box containing £10,000. The theft is reported but of the petty cash, not the bigger amount.
"Man Detained" is another rather loose adaptation of the work of Edgar Wallace, part of a whole series of B films made from 1960 to 1965.
Among the Edgard Wallace episodes I saw, that's probably one of the best. Intriguing, action packed, full of suspense, vivid at the most, I recommend it to all movie buffs fond of B UK noirs.