BMW bosses meet with union representatives today in a bid to avoid industrial action in a row over what Unite has described as "pensions robbery".
Unite has warned BMW to brace itself for "serious industrial action" involving some 7,000 car workers should the car company "continue to ignore their concerns".
Strikes are on the horizon at BMW plants which produce Minis in Oxford and Rolls-Royce vehicles in Sussex, after proposals to change workers' pensions from final salary schemes by 31 May this year, to less generous defined contribution plans.
Unite general secretary Len McCluskey made the warning in a letter to BMW, ahead of today's talks involving Unite reps, BMW bosses and McCluskey.
He said: “At a recent meeting of senior Unite shop stewards from all plants, I was able to gauge the concern, frustration and anger of our members. It is evident that, if we do not resolve the differences that exist, then the likelihood of serious industrial action will occur."
The dispute developed in the autumn after a consultation vote found 96 per cent of staff willing to strike if the changes were forced through.
BMW creates more than 200,000 Minis a year at its Oxford plant and walkouts would be the latest headache for the UK car industry.
It is currently in the midst of mounting concern over a prospective deal between General Motors and Peugeot maker PSA. GM is in talks to sell its European business to French firm PSA, including Vauxhall, which has led to fears over job losses.
PSA's chief executive is set to meet Prime Minister Theresa May this week, along with McCluskey, after GM met with business secretary Greg Clark and McCluskey last week.
Unite's boss has requested assurances similar to those given to Nissan to keep production at its Sunderland plant continuing after Brexit.