The Avro 707 originated as a proof-of-concept delta wing aircraft, built to test the tailless thick delta wing configuration chosen for the Avro 698 jet bomber — later named the Vulcan — and in particular to investigate the then poorly understood low-speed characteristics of such a configuration. Aerodynamically a one-third scale version of the Vulcan, the prototypes were ordered by the Ministry of Supply to Specification E.15/48, and production was accelerated by using components from other aircraft — the canopy of the first prototype was borrowed from a Gloster Meteor. On 4 September 1949, the first Avro 707, VX784, performed its maiden flight from RAF Boscombe Down, with Squadron Leader Samuel Eric Esler at the controls. Tragically, it was a flight programme marked from the very start by loss: on 30 September 1949, just weeks after its debut, the aircraft crashed near Blackbushe, killing Esler — the subsequent investigation concluding that a suspected control circuit failure had caused the air brakes to lock open, provoking a stall. Despite this heartbreaking beginning, the Avro 707 family gave British aircraft designers early confidence in the general handling characteristics of the delta wing, which led to its adoption on other aircraft types, and some of the systems tested found direct application on other military programmes. Without the sacrifice of VX784 and its pilot, Britain's delta wing story might have ended before it began.