Prior to the release of the Mustang on April 17 1964 the general image of Ford was that of a manufacturer that did not produce cars that appealed to young people or cars that had a sporty feel. This changed forever when a million Mustangs were sold in two years and set a sales record that stood for twenty years. It was the success of the Mustang that inspired Ford to produce a European version of their "personal coupe". Therefore in 1965 "Project Colt" was initiated to design a car with a similar feel to the Mustang but for the British market.
At the time the only vaguely sporty car available in the UK was the Lotus Cortina and for this reason Ford believed that their new project in the UK would be just as successful as the Mustang was in America. In 1964 various Ford styling and design studios in America and Europe were drawing up the first ideas for "Project Colt". By the beginning of 1966 the new car was being shown as full size mockups to "clinics" in London, Cologne, Milan and other European cities. In July 1966, following a favorable response to these initial designs Ford decided to follow the concept through to production. £20 million was allocated for the development budget with a view to releasing the car in the later half of 1968.
Some model Ford Mustangs are considered to be in a class of muscle car called pony cars. Mustang GTs and Boss were called pony cars because they were a smaller size vehicle than other muscle cars. These Mustangs still had to have top of the line performance engines and options to even be considered a muscle car though.