The Mirage project was conceived in the spring of 1967 after Ford decided to discontinue the GT40 programme. John Wyer, who ran J.W. Automotive Engineering at Slough in England, acquired a development project by English designer Len Bailey that aimed to improve the aerodynamics, mass, and suspension of the Ford GT40 Mk I.
Using a standard Mk I GT40 chassis as the foundation, the JWAE team made significant modifications. The greenhouse and front bulkhead were reshaped, and a more aerodynamically refined body was constructed. Carbon fibre was used in conjunction with fibreglass body panels — a technique described as the first application of this method in all of automotive racing. The composite approach would later carry over to the 1968 and 1969 GT40s that JWAE campaigned, as well as privateer cars of that era.
Engine choice evolved during early development. A 289 cubic inch Ford V8 was used initially, but by the time of the Le Mans test days the car had been fitted with various capacities up to 5.7 litres. The M1 completed its first run on 21 March 1967 and made Le Mans its first significant test.
A total of three M1 chassis were produced: M10001, M10002, and M10003.
When the Mirage appeared publicly, it wore the now-iconic powder blue and marigold colour combination of Gulf Oil — a departure from the deep metallic blue of previous Gulf-backed entries. This livery, unveiled with the M1, would become one of the most celebrated visual identities in motorsport history.
The highlight of the M1's racing career was the victory at the rain-soaked 1967 Spa-Francorchamps 1000 km, won by Jacky Ickx and Dick Thompson. The team also won the Kyalami 9 Hours with chassis M10001, which subsequently repeated that victory at Kyalami in 1968.
At Le Mans in 1967, the preliminary test sessions saw the M1s outperform the GT40s in lap times, though both cars retired from the main race. M10002 achieved ninth overall at the Monza 1000 km before being written off in an accident during practice at the Nurburgring 1000 km, when it struck a stationary Ginetta and was damaged beyond repair.
Chassis M10003 scored the first outright win for both JWAE and the Mirage marque at the 1967 Spa race, and also won at Karlskoga and Montlhery that season. For 1968, M10003 was rebuilt into a lightweight GT40 specification (designated P1074) and used as a camera car for the Steve McQueen film Le Mans.
M10001 is the only M1 chassis to survive today in its original configuration.
At the conclusion of the 1967 season, the FIA banned Group 6 cars with engine capacities over 5 litres that had fewer than 50 production examples, an attempt to contain the spiralling speeds and development costs associated with Ford's programme. JWAE attempted to argue that the Mirage qualified as a reworked GT40 for the Group 4 category, but the appeal was unsuccessful. The M1 did not race in the World Sportscar Championship after 1967.
The M1 nonetheless left a lasting mark on the sport. It proved that an independent constructor operating outside the factory programmes of Ford and Ferrari could achieve victories at the highest level of sports car competition. The Gulf livery introduced with the M1 would go on to adorn Porsche 917s, Ford GT40s, and eventually the GR8 that won Le Mans outright in 1975, making the M1 the origin point of one of the most celebrated partnerships in endurance racing history.
There has been persistent historical discussion about whether M10002, after being wrecked at the Nurburgring, contributed components to GT40 chassis P1075 — the car that won Le Mans in 1968 and 1969. Research has demonstrated that P1075 was a completely new chassis that received certain parts from M10002 along with upgrades developed during the M1 programme, rather than being a rebadged rebuild of the damaged car.