This comes from the Wikipedia entry

Describing the vehicle in 1941, a correspondent for The Light Car magazine reported “touching the 60-mark [60 mph (97 km/h)]” while following one along a road. Restricted vision meant the Beaverette driver had to rely on an observer to relay information about other road traffic and also to consider situations well in advance, for example when making a turn, the driver had to base his steering on “observations made something like ten yards [30.00 ft (9.14 m)] back.”

Doesn’t exactly inspire confidence but then this was the nation that gave us the Saro Lerwick. 😀