was removed, the side-by-side seats remaining. Following an extensive evaluation, the Balliol was chosen as the victor over the rival Athena, leading to sizable orders being promptly placed to replace some of the Harvards in RAF service. The RAF naming conventions for various types preferred that pure trainers, not conversion type trainers, should have names related to education or places of learning e.g. Airspeed Oxford, Avro Tutor and Athena, the Percival Prentice and Provost and De Havilland Dominie. Balliol is an Oxford University College and it alliterated with 'Boulton Paul'. Further development A specialised model for the Royal Navy's Fleet Air Arm (FAA), designated Sea Balliol T.21, was also developed. Various design changes were made to the aircraft as to better adapt it for shipboard use on board the service's aircraft carriers. These included the fitting of an arrestor hook, which was necessary for landings at sea. While the Balliol was successfully introduced to service during 1950, its fortunes had dramatically changed within a single year. This was largely due to attitudes amongst staff at the Air Ministry having shifted once again on the topic of training requirements, with the RAF now wanting a jet-powered advanced trainer aircraft instead. This would result in the procurement of the rival de Havilland Vampire T.Mk11 at the Balliol's expense. Design The Boulton Paul Balliol is an advanced trainer aircraft, being configured for use by military operators. In terms of its basic configuration, it was relatively traditional, featuring a conventional landing gear, of which the two main gear were retractable but the tailwheel was not. Having anticipated student pilots being particularly rough on the aircraft, it was designed to be both durable and as easy to maintain as possible, featuring around 40 inspection hatches, typically secured by quick-release fasteners, across the fuselage to facilitate this. For greater simplicity of maintenance, wherever feasible, components were designed to be interchangeable, such as the fin, tailplane, wing tanks, main gear oleos, and other elements. Structurally, the Balliol comprises seven main sections, three of which form the fuselage, two for the wing sections, and the remaining two for the tail unit. The majority of exterior covering was light alloy stressed-skin, supported by a combination of subframes and longerons, while the rear section incorporated a monocoque approach. Fuel was accommodated within a mixture of wing tanks and a single fuselage tank, the former being easy to remove while the