Subsequent investigation of the accident traced the failure to faulty design of the wing leading edge section ahead of the main spar. The design had been satisfactory for the earlier Vampire and Venom but not for the higher stresses induced by the rolling pull-out manoeuvre at 650 mph flown by the DH110 prototype at Farnborough. The leading edge skin, without the extra reinforcing structure that would be added later, buckled, which resulted in the outer portions of the swept-back wings being torn off (similar display routines had been flown on preceding days by the other prototype DH110 which had an aerodynamic fence providing external stiffening for the skin located precisely over the area where the buckling originated.). The subsequent shift in the DH 110's centre of pressure caused the aircraft to pitch up, the cockpit and tail sections breaking away and the engines being torn from the airframe by the g loading. One of the engines hit an area crowded with spectators at the end of the runway, causing the majority of the deaths. Other spectators were injured by debris from the cockpit landing close to the main spectator enclosures alongside the runway. This incident led to a restructuring of safety regulations for air shows in the UK, and no member of the public died as a result of a British airshow flight for more than 62 years, until the crash of a Hawker Hunter warplane killed 11 people during the Shoreham Air Show on 22 August 2015.