The merger between Fiat Chrysler and PSA Group, which includes the Ellesmere Port and Luton Vauxhall/Opel plants, has been welcomed by the Unite union.

The merger, which has won approval from both sets of shareholders, will create the world's fourth biggest carmaker. Vauxhall employs 3,000 staff in the UK.

Unite said the merger, allied with the post Brexit free trade deal with the EU, should pave the way for new models to be produced in the UK.

However, the union was seeking confirmation the company would stand by its previous announcement that there would be no plant closures here.

Unite national officer for automotive industries Des Quinn said: "This merger is good news for our members at a bleak time for the UK economy.

"We welcome the approval of both sets of shareholders to create the fourth biggest global carmaker and will seek reassurance the new merged company will continue to commit to no plant closures, as was previously announced in November.

"Specifically in the UK, we call upon PSA to look at a longer term plan to build electrified vehicles at both Luton and Ellesmere Port with future regulatory and legislative changes in mind.

"At Ellesmere Port, it is also now time for our members to be rewarded for their ongoing commitment and having met all cost requirements to be awarded new product – currently, it is the only plant in Europe not to have been.

"Previously the management have said this decision would not be made until there was a clear understanding on the outcome of discussions between the British government and the European Union (EU).

"Now the free trade deal with the EU has been agreed by both sides with no tariffs or quotas, this should create the necessary business environment the company was seeking.

"Therefore, there should be no further delays in announcing new models at Ellesmere Port."

The combined company Stellantis will combine the PSA brands Peugeot, Citroen and Vauxhall/Opel with FCA's Fiat, Jeep and Chrysler.

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