Future production agreements at Nissan's Sunderland plant, including a contract to build Renault models, hinge on the strength of the pound against the euro, according to executive vice president Patrick Pelata.

He said: "If there is no problem with the currency we would go for Sunderland for maximum production because it is the best plant in Europe in productivity and quality terms." Decisions on future models, including the Micra, Almera replacement and Renault Clio, were "some way off", Mr Pelata added.

"My best wish is that it will happen for Sunderland again. But there is no substitute for production profitability. One day we will have to look at raising our own capacity or using Renault's."

Mr Pelata was critical of rival manufacturers that shared components across several brands.

He accused VW of being "dogmatic" about sticking with common parts, which could weaken individual model identities and driving characteristics.