Barnes alleges that some officials, including Godfrey Lee and Charles Joy, favoured metal construction for greater strength; other figures desired the ability to explore the Dutch roll phenomenon and take-offs (both necessitating a powered aircraft). For a variety of factors, development of the T.48 was terminated and a revised specification around a self-propelled aircraft was issued during December 1959. Powered The British aircraft manufacturer Handley Page, who had submitted their HP.115 proposal, was authorised to proceed with construction of a single aircraft. This work was largely undertaken at the firm's existing facility in Cricklewood. The HP.115 featured a delta wing of very low aspect ratio, which was swept at 75° and featured trailing edge elevons, spring servo-tabs, and anti-balance tabs to provide optimal lateral and longitudinal sensitivity. Infinitely variable perforated air brakes arranged as split flaps were present at 50% chord, and were actuated pneumatically using a pre-charged air bottle. The airfoil section was a modified bi-convex type with the maximum thickness at 4% of the chord. This section was chosen as being representative of the type likely to be adopted for a supersonic transport. It had a favourable chordwise distribution of cross-sectional area and hence a low wave drag in supersonic flight. A unique plywood leading edge was employed wherein new sections of different degrees of camber could be substituted, although in practice this feature was never used. The cockpit accommodated its pilot, who was seated upon a Martin-Baker-built ejector seat, underneath a sliding canopy. Cockpit instrumentation included an airspeed indicator, altimeter, yawmeter, electric turn-and-slip indicator, artificial horizon, directional gyro, and a stand-by compass. No lighting was provided, enabling a relatively small battery for the turn-and-slip indicator to suffice. Manually operated flight controls were present, which incorporated a differential gearbox arrangement. Hydraulically-actuated wheel brakes, operated by foot pedals in the cockpit, were also provided. When required, additional deceleration was available via a drogue parachute stowed at the base of the rudder. Information such as airspeed, altitude, angles of incident, and other criteria were captured primarily by a pair of synchronised flight recorder. The aircraft was provided with a fixed tricycle undercarriage, which was derived from the main gear of a BAC Jet Provost Mk 1 and the nosegear from a Jet Provost Mk 2. The fuselage, which was largely constructed of conventional aluminium alloys, comprised a shallow rectangular section girder, with a nacelle at the nose to house the