Smokescreen (1964)

This is quite an interesting yarn about an insurance assessor "Roper" (Peter Vaughan) sent to look into a large claim after a businessman goes missing. Fairly swiftly, he discovers it's really a case of potential murder and his naturally inquisitive, meticulous, nature encourages him to investigate. It's not too long before he is embroiled in a tale of money, debts, adultery and corpse-hunting. It's not exactly the stuff of Hercule Poirot, and the production is all a low-budget affair, but Vaughan carries it all off quite well as he tries to pull together the threads of infidelity and fraud, and with solid supporting contributions from John Carson and Yvonne Romain to keep the waters muddy for a time, it passes an hour effortlessly enough.