Unite has threatened Ford with legal action over staff who lost their pension when Visteon UK went into administration last year.
The union's lawyers have written to Ford seeking compensation for former Ford employees who transferred to Visteon UK and lost their pension after receiving "misleading" advice from the automotive manufacturer.
Unite claimed the information provided led the workers to believe their pensions would be secure if they transferred their Ford benefits to the Visteon UK pension scheme in May 2000.
However, Unite said 610 workers at plants in Basildon, Belfast, Enfield and Swansea lost their jobs and some of their pension when Visteon UK went into administration last year.
Unite national officer Roger Maddison said: "Hundreds of workers, many of them close to retirement, were sacked at a minute's notice and lost their pensions. We believe Ford misled many of these workers leading them to believe their pensions were safe with Visteon.
"Ford failed to clearly set out the risks associated with transferring the assets staff had built up with Ford - now many of these workers face vastly reduced pensions."
However, Ford said it met or exceeded its obligations under the 2000 agreement when Visteon became fully independent. It said the agreement covered the transfer of employees to Visteon UK and their pensions into the Visteon fund.
A statement from Ford said: "The situation for former Visteon UK employees is unfortunate but the responsibility for administering and funding their terms and conditions was Visteon's, including managing its pension fund. Ford's obligations to its former employees were fully discharged and Ford believes there is no basis for resuming liability for benefits transferred to Visteon.
"Ford has stated that it will not provide further assistance to affected parties. This position was confirmed at a meeting on 22 January between senior Ford executives, representatives of the Unite union and ex-Visteon employees."
In March, Unite said it was committed to pursue a legal challenge against Ford based on promised "mirrored terms and conditions" and "pension safeguards" given at the time of spin off (PP Online 2 March).
The Visteon pension scheme is currently in the Pension Protection Fund assessment period. Unite said workers will only get PPF level benefits for any accrued Ford pension rights that they transferred - and for their accrued VUKPP pension rights.
In April the PPF and Visteon UK scheme trustees filed a $550m (£350m) claim against US Visteon Corporation to recover money for the fund (PP Online 14 April).
However, just a month later the claim was withdrawn after the trustee concluded the costs and risks of pursuing litigation outweighed the likely benefits (PP Online 13 May).
