Mr Ghosn said Britain staying outside the eurozone might persuade Nissan to switch production of new Micra to mainland Europe.
The combined group stands to make substantial savings by assembling Micra and new Renault Clio on the same line. Senior Renault/Nissan executives have said the group is also seeking UK grant assistance with the message that Spain and France were “waiting in the wings”.
The euro political stakes were further raised this week with the leaking of a confidential memo to Mr Byers. Andrew Fraser, head of the Invest in Britain Bureau, warned of “possible meltdown” of the UK manufacturing base unless the Government showed commitment to adopting the euro.
But in an interview with Automotive Management, Mr Byers said Nissan's hesitation in deciding whether to continue UK Micra production was not entirely linked to adoption of the euro.
Until the statement by Mr Ghosn, there was optimism in the UK that Nissan's Sunderland plant might produce next-generation Micra and Clio from 2002.
Known as 'le cost cutter', Mr Ghosn is architect of the Renault-Nissan Alliance's £6.3bn global cost-cutting “recovery plan”. He is shutting five Japanese plants and cutting 21,000 Nissan jobs.
He told the Financial Times: “You cannot have costs in a strong currency when most of your revenues are in a weak currency.”
Nissan Sunderland's Europe-leading productivity in recent years is the prime reason for Mr Ghosn delaying a decision on switching Micra production.