Added to that, Barnard won the Kartmasters British Grand Prix on two occasions, as well as winning the LGM Series in the IAME Cadet category.

[2] The Briton moved onto the European stage in 2018, racing in the OK Junior class for KR Motorsport, for whom he would win the WSK Final Cup at season's end.

[3] Having become a karting protégé of Nico Rosberg and joined the Formula One World Champion's Racing Academy, Barnard progressed into the OK Senior category the following year.

[7] Barnard remained with Rosberg Racing Academy for his final karting season in 2020, where he once again ended up as the runner-up of the World Championship, this time losing out against Callum Bradshaw.

For 2021, Barnard partnered up with BWR Motorsports, a team affiliated with his mentor Nico Rosberg, to compete in the ADAC Formula 4 Championship.

[14] Nevertheless, Barnard remained in Formula 4 the following year, driving for newly-formed team PHM Racing alongside Nikita Bedrin and Jonas Ried.

[15] He began the year by competing in the F4 UAE Championship in January, taking his and his team's first win in car racing at the Yas Marina Circuit.

[21] Having started out with two sixth places and a collision with teammate Ried at Spa-Francorchamps, the Briton experienced a more positive weekend in Hockenheim, taking a pair of podiums.

[27][28] During the opening months of 2023, Barnard competed in the inaugural Formula Regional Middle East Championship with PHM Racing.

[43] In January 2023, Barnard was announced as the final driver for Jenzer Motorsport to complete its lineup for the 2023 season, alongside Bedrin and García.

[53][54] The final round in Monza saw another impressive showing from Barnard, as he placed fourth and third in the races, taking another podium in the latter amidst multiple battles.

[55] His late run of form allowed Barnard to finish tenth in the championship standings, taking 72 points and three podiums throughout the season.

[56][57] In September 2023, Barnard was named as one of four nominees for the Aston Martin Autosport BRDC Award, alongside Formula 4 racer Arvid Lindblad and GB3 Championship drivers Callum Voisin and Joseph Loake.

[58] In February 2024, it was announced that Barnard would graduate to the 2024 season of the FIA Formula 2 Championship with PHM AIX Racing partnering Joshua Dürksen.

[72] Barnard made his Formula E debut at the Monaco ePrix with McLaren from FP2 onwards to deputise Sam Bird who suffered a hand injury from a crash in FP1.