Royal Air Force boy entrants
Under the RAF boy entrant scheme which ran from the mid-1930s to late 1965, boys joined the Royal Air Force between the ages of 15 and 17 and were trained in various occupations (or trades) which fitted them for employment in the RAF. Training was suspended during World War II but recommenced in May 1947. The final entry was the 51st who commenced training in January 1964 and graduated in July 1965.
Source: Wikipedia — Royal Air Force boy entrants (CC BY-SA 4.0)