McGuire entered two Formula One British Grands Prix. With his privately-run Williams FW04 at the 1976 British Grand Prix, he found himself as a reserve entry and was denied a chance to compete. For the 1977 race, he entered his self-built McGuire BM1, based on the Williams FW04, but failed to pre-qualify. He was killed practicing this car during a minor meeting at Brands Hatch later that year.
|1976||Brian McGuire||Williams FW04||Cosworth V8|| BRA|| RSA|| USW|| ESP|| BEL|| MON|| SWE|| FRA|| GBR|
| GER|| AUT|| NED|| ITA|| CAN|| USA|| JPN||-||0|
|1977||Brian McGuire||McGuire BM1||Cosworth V8|| ARG|| BRA|| RSA|| USW|| ESP|| MON|| BEL|| SWE|| FRA|| GBR|
| GER|| AUT|| NED|| ITA|| USA|| CAN|| JPN||-||0|