A settlement has been reached to offer compensation to former workers at Visteon, five years after the car parts company went into administration, hitting employees' pensions.
Unite said it had concluded an agreement with Ford, which hived off the car parts business to Visteon over a decade ago.
It is understood that around 1,200 ex-workers from factories in Basildon, Essex, Enfield in north London, Belfast and Swansea, will be covered by the settlement.
Unite said in a statement: "Unite has concluded an agreement with Ford to make a settlement offer to eligible ex-Visteon employees who filed legal claims in connection with reductions in their pensions resulting from Visteon UK being put into administration in 2009.
"The settlement would avoid further expense for participants in the case and will settle the legal claims that these individuals have made against Ford.
"Unite and Ford have been involved in lengthy but constructive discussions to reach a position where a settlement has been offered.
"Details of the settlement are confidential and a private matter for those directly involved."
Over 100 former Visteon workers travelled to London today to hear news of the announcement, which will now be discussed at a series of meetings before the agreement is finalised.
The Visteon Pension Action Group has been campaigning for years for action to restore pensions to those affected, some of whom lost up to half of their pensions following the administration.
Sources in the group said the agreement could be worth millions of pounds.
The plight of the workers was discussed in the Commons last year, with MPs pressing for a deal to make good the losses suffered by the workers.
Prime Minister David Cameron congratulated all those involved in securing the deal, including a cross-party group of MPs and Unite the union.
During Prime Minister's Questions, Mr Cameron said: "I wholeheartedly agree with you, this is a good development for pensioners and all those who have played a role and I think there are MPs on all sides of the House who have been involved with this and I think they are to be credited for the work they have done with Ford to make sure we get this justice."
Stephen Metcalfe, Conservative MP for South Basildon and East Thurrock, who chairs the all party parliamentary group in support of Visteon pensioners, said: "I am delighted to hear that Ford are living up to their responsibilities and doing the right thing.
"This is fantastic news for the Visteon Pension Action Group (VPAG) and for Visteon pensioners across the UK and I would like to congratulate VPAG for their hard-fought campaign.
"Their dogged determination has resulted in a well-earned victory and I know that the people they represent will be forever grateful for their efforts.
"I would also like to thank Ford for honouring their responsibilities. By righting this wrong, they have restored their proud reputation for looking after their workers."
Sian James, Labour MP for Swansea East who joined protesters outside the House of Commons, praised the effort of workforce, trade unions and fellow MPs in getting to this stage.
"This campaign for justice has been unique in that it has gained cross-party support both in Westminster and Cardiff Bay," she told the crowd of more than 200 former car workers.
"You have put forward forceful and compelling arguments and it appears that Ford have listened."