The future of Luton and the Vauxhall Vivaro van plant will be clear within a year.
The current van range, built to be branded additionally as Renault Trafic, Nissan Primastar and Opel Vivaro, has to be replaced in 2013.
That means that design of the new platform starts next year, and that means the three partners have to commit to a long-term contract or walk away.
General Motors was the lead engineer on the present Vivaro.
Renault was the design authority and Nissan, which came late to the party under the Renault Nissan alliance, had no input though it may be expected to demand work-share this time and to volunteer its Barcelona plant for manufacture.
The van has been a huge success with sales rising from 10,000 a year in the year 2000 to 50,000 now. It is second only to Ford in the UK.
Luton builds all the standard height vans. The high roof vehicles come from the Nissan plant in Barcelona. Luton is however the only assembly building in the European network big enough to handle the standard van.
Nick Reilly, who was recently appointed as the new president of GM Europe, said: “If the talks with Renault do not come out positively we need to look for something different.
“Our intention is to find another product.”
Business Secretary Lord Mandelson said: “I am pleased. There was never quite the degree of commitment from Magna that we now seem to be getting from GM.”