Logos of Peugeot and Fiat are seen in this illustration picture taken October 30, 2019. REUTERS/Regis Duvignau/Illustration

LONDON (Reuters) - Britain’s biggest union is seeking guarantees on the long-term future of Peugeot’s plants in Britain after the French carmaker struck a binding deal on Wednesday with Fiat Chrysler to create the world’s fourth-biggest carmaker.

Peugeot operates a car factory in northern England where it builds the Opel/Vauxhall Astra.

In June, the automaker issued an ultimatum saying the decision to build the next generation of the vehicle at the site “was conditional on the final terms of the UK’s exit from the European Union.”

The Unite union said on Wednesday it was seeking an urgent meeting with bosses.

“Unite will ... be seeking guarantees about new investment to ensure that the company’s UK factories are able to continue to build high quality cars and vans to meet the challenges of the transition to electric vehicles,” said national officer Des Quinn.