The chief executive of Vauxhall-owner PSA says it could move all production from its Ellesmere Port factory if Brexit makes it unprofitable.
Carlos Tavares told the Financial Times that the carmaker has alternatives to the plant which it could use.
The move would probably lead to the closure of the site, the FT said, threatening 1,000 jobs.
That would leave Vauxhall’s Luton-based van plant as its last presence in the UK.