The ADO74 was a series of prototype supermini mockups produced by British Leyland before the project was cancelled in 1973. The project was cancelled as British Leyland could not raise the £130m needed to produce it.

The project was led by Harry Webster but he had little experience in the small car market. As a result, the project drifted, directionless. In a short amount of time, the ADO74 grew from being a Mini replacement, into something rather larger. Indecisiveness over the styling also resulted in many proposals being produced, none of which the BLMC management were entirely happy with.