Found it at last on Wiki, NK, ... Twenty Questions!
The BBC aired a version on the radio from 1947 to 1976 with TV specials airing in 1947 and 1948 plus a series from 1956-1957. On radio, the subject to be guessed was revealed to the audience by a "mystery voice" (originally Norman Hackforth from 1947-1962; he was later a regular panelist). The series was originally presented by Stewart MacPherson. The panel comprised Richard Dimbleby, Jack Train, Anona Winn and Joy Adamson, in later years comedian Peter Glaze also. A revival ran for one season in the 1990s on BBC Radio 4, hosted by Jeremy Beadle. The BBC World Service broadcasts a version called Animal, Vegetable and Mineral, chaired by Terry Wogan with a panel including Michael Flanders.