and Tyrrell, Thackwell had been signed by Ken Tyrrell to be a test driver for the Tyrrell F1 team, alongside his F2 campaign. He was invited to the Dutch Grand Prix by Tyrrell as a spectator, both to learn about the track and the Tyrrell 010 when Arrows team boss Jackie Oliver approached him after the first unofficial practice session to ask if he'd like to drive the Arrows A3. Oliver's regular driver, Jochen Mass had been injured at the previous grand prix, but his car was at Zandvoort. Although the car was still set up for Mass, including his seat and pedal arrangement, Thackwell got permission to drive the car from Tyrrell and though he failed to qualify, eventually set a faster time than Keke Rosberg in the Fittipaldi. He made his official debut a few weeks later, when Tyrrell made the third car available for him at the Canadian Grand Prix. Because he took part in this event, Thackwell was often listed as the youngest driver to start a Formula One race, but this claim is arguable. On the first lap of the race, Alan Jones and Nelson Piquet collided at the first turn and were subsequently hit by a number of other cars, including Jean-Pierre Jarier and Derek Daly, both driving Tyrrells. Thackwell negotiated his way through the carnage and returned to the start/finish line undamaged by which time, the race had been red flagged. As both Jarier's and Daly's cars were too badly damaged to repair quickly, Thackwell was instructed by Ken Tyrrell to give up his car for Jarier. Under Formula One regulations, when the race is stopped after less than two full laps, the original start is declared null and void and the race starts anew. If a driver cannot bring their car back to the second start, they have technically not taken part in the Grand Prix. Using these criteria, Ricardo Rodríguez remained the youngest race starter until Jaime Alguersuari broke the record at the 2009 Hungarian Grand Prix; a record that was subsequently broken by Max Verstappen in 2015. Thackwell had another opportunity at the next race with Tyrrell, the United States Grand Prix. After he suffered a fractured brake disc during qualifying, he was unable to qualify to race at Watkins Glen. Between Formula One Thackwell's debut in a Tyrrell was unsuccessful; he returned to Formula Two in 1981. He was