Its length, slender cross-section and intended purpose led to its being nicknamed the "Flaming Pencil". The aircraft had its genesis in Operational Requirement 330 for a high speed (Mach 3) reconnaissance aircraft, which eventually developed into the Avro 730. As the 730 was expected to operate at high speeds for extended periods of time, more data was needed on high speed operations, leading to Operational Requirement ER.134T for a testbed capable of speeds greater than Mach 2. The aircraft was expected to run at these speeds for extended periods of time, allowing it to study kinetic heating effects on such an aircraft. The aircraft was expected to spend a considerable amount of time with a skin temperature around 300 Celsius. Several firms took interest in this very advanced specification and the eventual contract (6/Acft/10144) was awarded to Bristol Aircraft in February 1953. Bristol gave the project the type number 188, of which three aircraft were to be built, one a pure test bed and the other two (constructor numbers 13518 and 13519) for flight testing. Under contract number KC/2M/04/CB.42(b) serial numbers XF923 and XF926 were given on 4 January 1954 to the two that would fly. To support the development of the Avro 730 Mach 3 reconnaissance bomber, another three aircraft were ordered (Serial Numbers XK429, XK434 and XK436). The follow-up order was cancelled when the Avro 730 programme was cancelled in 1957 as part of that year's review of defence spending. The 188 project was continued as a high speed research aircraft. For more details of development and design, and operational history, click here.