In 1980, having tested for both Ensign 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.