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.
| Yr | Entrant | Chassis | Engine | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | WDC | Points |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1976 | Brian McGuire | Williams FW04 | Cosworth V8 | BRA | RSA | USW | ESP | BEL | MON | SWE | FRA | GBR DNP | 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 DNPQ | GER | AUT | NED | ITA | USA | CAN | JPN | - | 0 |