Shame on the BBC - Donald Campbell's speed of 403mph was set on Kati Thanda-Lake Eyre, the huge salt pan in central Australia.
It was the last official mark to hold the land speed record with a wheel-driven vehicle. All subsequent records have been set by jet or rocket-powered cars.
Someone check my math but I am pretty sure 409.277, FIA sanctioned, Nov 12 1965 is faster than 403mph unless 4wd doesn't count but I'm pretty sure the clue is in the name there.