Ensign was a Formula One constructor from Britain. They participated in 133 grands prix, entering a total of 155 cars.
Ensign scored 19 championship points and no podium finish. The best result was a 4th place at the 1981 Brazilian Grand Prix by Marc Surer.
The team was founded by Morris Nunn who also carried out design duties during the first two seasons of the team's existence. Nunn would later go on to be a prominent chief engineer in the American-based Champ Car series, winning championships with drivers Alex Zanardi and Juan Pablo Montoya in the late 1990s.
After the end of the season, Ensign was merged into the Theodore team, which it had previous ties to via financier Teddy Yip, and took that team's name. During many seasons, the connection between Ensign and Theodore was so great that in some years they used almost the same car, akin to how Red Bull Racing has a second but separate team called Toro Rosso in more recent times.
Ensign driver Roberto Guerrero continued on with the newly merged team for , as did the team's main car designer. The entire Theodore F1 team did not last the 1983 season, though, and shut down late in the year.