The Boulton Paul Balliol was the last British aircraft powered by the iconic Rolls-Royce Merlin engine. Also, the Balliol was the last piston-powered advanced trainer in both the Royal Air Force and the Fleet Air Arm, and yet it began life as the world's first turbo-trainer. Conceived in the last days of the Second World War as a new trainer to be powered by a revolutionary turboprop engine, it became the first aircraft to be powered by a single prop-jet, beating the rival Avro Athena into the air by just two weeks. Policy was to change and it went into production powered by the trusty Merlin and Boulton Paul hoped for huge orders with a second production line opened at Blackburn Aircraft. Yet, policy was to change again and in the end only 200 planes were built as the RAF decided to switch to all-jet training. A dozen were sold to the Royal Ceylon Air Force and as yet another footnote in aviation history, the Balliol became the last aircraft built by Boulton Paul who were world leaders in the production of power controls such as its famous machine-gun turrets that saw action in the Second World War.