Vauxhall have pledged to built its new Astra model at the Ellesmere Port plant.
PSA Group which own the car manufacturer outlined its plans from 2021 but only if a no-deal Brexit is avoided when the UK leaves the European Union.
The French company also said that a new vehicle agreement struck with the Unite union would need to be ratified in order to proceeed with the proposal.
Vauxhall’s current Astra models are still built at the firm’s base in Ellesmere Port, which first opened in 1962, as well as in its Polish operation in Gliwice.
But PSA insist that Britain’s post-EU arrangements will determine whether the Cheshire plant will continue the manufacturing process for new vehicles.
In a statetement, they said: “The decision on the allocation to the Ellesmere Port plant will be conditional on the final terms of the UK’s exit from the European Union and the acceptance of the New Vehicle Agreement, which has been negotiated with the Unite trade union.”
Boris Johnson, the current forerunner to become new Prime Minister, has vowed to take the UK out of the EU on no-deal terms at the end of October’s deadline.