The Commons work and pensions committee is to investigate the sale of Vauxhall to PSA Peugeot Citroën.
The disclosure coincided with bosses at the Geneva Motor Show giving warnings about the future of the British automotive sector if it is forced out of an EU customs union and single market.
The committee, led by the campaigning MP Frank Field, played an instrumental part in forcing Sir Philip Green to pay £363 million into the pension scheme of the bust BHS retail group.
It began a fresh inquiry into that settlement yesterday, as well as raising questions about the fate of Bernard Matthews pensioners after the sale of the business to Boparan Holdings.
With Vauxhall, the committee wants to know whether its sale by General Motors will hit the pensions of thousands of past and present workers at its Luton and Ellesmere Port factories.
There are thought to be about 15,000 members in the Vauxhall scheme. Current workers are likely to see final salary arrangements replaced with a defined contribution scheme that will reduce their benefits by about 15 per cent.
About 4,800 workers have yet to be given commitments beyond the early 2020s as to whether PSA intends to keep manufacturing in the UK because the French group has also taken over Opel. It is reckoned that the GM(UK)/Vauxhall scheme has a deficit of £840 million.
Mr Field has written to Rob Assinder, chairman of the GM(UK) pension trustees to know what role they played. Mr Assinder, a former senior GM finance executive in the UK who became pensions director six years ago, has been asked whether he was party to negotiations; what assurances were given about the scheme; what dialogue he had with The Pensions Regulator; and whether the trustees are happy.
Mr Field has also written to Lesley Titcomb, chief executive of The Pensions Regulator, to establish whether it has been involved in the sale, whether there is any “material detriment” to members of the scheme, and what steps the watchdog has taken to satisfy itself.
Tata Steel closed the old British Steel pension scheme to accruals after thousands of workers voted in favour of it as a quid pro quo for keeping their jobs.
A consultation process on the closure of the final salary scheme at Royal Mail is in its final days. Postal unions have threatened industrial action if it closes.
In Geneva, Jim Farley, head of Ford Europe, which makes car engines in the UK, said a “zero-tariff environment” was vital for its employees in the UK. Ian Robertson, sales chief at BMW, cited tariff-free access as key in a decision this summer on whether to build the new electric Mini at its Oxford plant.
Robert Lea, The Times