Japanese car giant Nissan would "reconsider" its future investments in Britain if it left the European Union, its chief executive has warned.
Speaking at the launch of Nissan's new Qashqai model, CEO Carlos Ghosn said: ""Obviously it's going to be a major factor happening and we are going to need to consider what does it mean for us for the future.
"If anything has to change we (would) need to reconsider our strategy and our investments for the future."
Nissan's new Qashqai will be built at Nissan's Sunderland site, which employs 6,500 workers. The firm has previously warned against a British exit, with chief operating officer Toshiyuki Shiga saying it would be an "obstacle" for the car giant.
The mounting debate over Britain's membership of the European Union comes as MPs prepare to vote on a bill legislating for a referendum by 2017 if the Tories win the general election in 2015.
Lord Digby Jones, former director of the CBI trade body, warned that the EU was a "job destroyer" and that a British exit would not be "unattractive".
John Mills, co-chairman of the Business for Britain group, which is seeking reform of the UK's EU membership, told BBC Radio 4's Today programme: "If Britain were to leave the EU - and that's not what Business for Britain is advocating - I think that Nissan and any other car company would have to take a view as to what the prospects were, particularly if we continue to have free trade with Europe, which is very likely to happen.
"What we are saying is that if there's renegotiation then a much larger proportion of British business would want to stay in. I think Mr Ghosn would be wise to support what we say, which is to push for these negotiations to be successfully accomplished."