[2][3] She entered an un-blown Frazer Nash for him to drive at Brooklands, and would stand in the pits opening golf umbrellas adorned with various symbols in order to pass information onto him during races.

[10][11] In 1934, Mitchell-Thomson led a team of three Frazer Nash drivers to fourth place in the Light Car Club's annual Relay Race at Brooklands.

Lagonda built two cars for the race; Mitchell-Thomson purchased one and entered with Lord William Waleran as co-driver.

The team gave strict instructions not to exceed a pre-determined average speed based on the 1938 event, to ensure that the untried design went the distance.

The cars did not challenge the likes of Bugatti and Delage, the former setting a new distance record, but impressed the British motoring press by securing third and fourth positions.

[26] He set the third-fastest practice time, but the event was cancelled due to the mobilisation of troops and war began within days.

[31][32][33][34][35] In 1949, Mitchell-Thomson purchased a Ferrari 166 MM and entered it for the 24 Hours of Le Mans alongside Luigi Chinetti.

Recognising that Chinetti was the quicker driver, Mitchell-Thomson allowed him to drive most of the race, taking a single one-hour stint between 4:26 a.m. and 5:38 a.m. once a three-lap lead had been established.

Mitchell-Thomson made a cameo appearance in the Will Hay film Ask a Policeman, in which the main characters end up on the Brooklands circuit after a police chase and get mixed up in a motor race.