The number of cars made in the UK tumbled 11 per cent last month, as incoming emissions standards and seasonal adjustments hit production.
A total of 121,051 cars were produced in July, falling from 135,954 cars in the same month last year, according to the Society of Motor Manufacturers and Traders (SMMT).
Year-on-year domestic demand plunged 35 per cent, while exports fell by 4.2 per cent.
Yet overall exports for the year have dropped by a smaller figure of 1.2 per cent, and continued to make up four in every five cars produced in the UK.
SMMT boss Mike Hawes called for political and economic clarity on the back of the results, adding that there was a need for "the continuation of beneficial trading arrangements with the EU and other key markets."
However, Hawes urged caution when looking at today’s statistics: "While the industry is undoubtedly feeling the effects of recent uncertainty in the domestic market, drawing long-term conclusions from monthly snapshots requires a health warning.
"The bigger picture is complex and month-by-month fluctuations are inevitable as manufacturers manage product cycles, operational changes and the delicate balance of supply and demand from market to market."