Founded in the 1960s, as a works team for Mobil, the club, initially named Pegasus (Coryton), won the Essex Intermediate Cup in the 1969–70 season, beating Hornchurch Reserves 2–0 in the final.

In the 1971–72 season, they finished third place out of nine clubs, once again winning the Essex Intermediate Cup at the end of the season, beating Colchester-based club Eastern Gas in the final.

[1] However, in the following season, they resigned from the league after playing only one match, losing 11–1 against Tiptree United on 2 September 1972.

Pegasus' last game came against Barkingside in a 15–2 loss in the FA Amateur Cup on 9 September 1972.

[2] Originally playing in Coryton, near Thurrock, at the Pegasus Club on Herd Lane,[2] the club later moved to the Southend Stadium, former home of Southend United between 1934 and 1955, upon joining the Essex Senior League.