john hosier was born in the northwest london suburb of kingsbury, middlesex. his father, harry hosier, was the founder of the building firm hosier and dickinson, and his mother, constance, was a violinist. she overcame the problem of his playing a musical instrument by teaching him to play the xylophone. he attended fryent primary school, kingsbury, preston manor county grammar school, now preston manor high school, wembley and st john's college, cambridge where he also served as a director of footlights from 1950–1951.