Car production slumped 55.3% in April, according to latest figures.
The data was released by the Society of Motor Manufacturers and Traders and also revealed commercial production was down 65.2% this month.
Only 68,258 cars were built in the UK in April and 7,655 commercial vehicles.
The SMMT hopes the Government's scrappage scheme, whereby people can trade in a car more than 10 years old and get £2,000 off a new vehicle, will stimulate sales but feels a recovery could take time.
Paul Everitt, SMMT chief executive said: “With the scrappage incentive scheme fully operational, industry is optimistic about the positive impact this will have on the market and on UK production facilities."
“Despite the current difficulties, the UK must prepare for the return of global growth and government support for the industry is an essential part of the process.”