In my view, this is the weaker of the four "Miss Marple" films made by George Pollock for MGM. Margaret Rutherford is flawless as the trustee of a charity charged with the rehabilitation of young offenders and Lionel Jeffries provides the laughs as the Captain of "HMS Battledore" - the sailing sloop that is used to convert these youngsters from their recalcitrant ways. As one of her fellow trustees suddenly - and literally - snuffs it, "Miss Marple" suspects foul play and with the help of a home chemistry set (and, "Mr. Stringer", of course) deduces that he was ingeniously poisoned! She sets…