UK road hauliers who paid over the odds for trucks from firms found to have colluded in a price-fixing cartel could be in line for £5bn in compensation.
That is the size of the payout sought by the Road Haulage Association, which is pursuing a claim on their behalf at the Competition Appeal Tribunal.
The move comes two years after the European Commission fined a number of truckmakers for inflating prices.
If the claim succeeds, trucks sold between 1997 and 2011 would be covered.
"Those truckers that have signed up to our claim could be in for a possible windfall of over £6,000 for every truck they bought or leased during the 14-year period," the Road Haulage Association (RHA) said.
More than 600,000 UK-registered trucks are involved and the £6,000 "is the estimated overspend figure that hauliers paid for each vehicle", it added.
Analysis: Theo Leggett, business correspondent
Cartels are great for their members, not so good for consumers. They effectively eliminate competition and push up prices.
Some of Europe's biggest manufacturers were working together to fix the cost of their trucks for fourteen years.
Inevitably, this will have meant their customers paid over the odds for their vehicles.
The European Commission has already imposed huge fines on the cartel members. That might discourage other cheats - but it doesn't help the victims.
The Road Haulage Association insists its members are angry, and it's pushing for compensation, both to remedy some of the damage that's been done - and to highlight what it regards as a major scandal.
In July 2016, four truck manufacturers - Daimler, DAF, Iveco and Volvo/Renault - were fined a record €2.93bn (£2.46bn) by the EU for colluding on prices and passing on the costs of emissions-reducing technology.
MAN, owned by Volkswagen, avoided a fine as it blew the whistle on the cartel.
In September last year, Scania, which held out and would not co-operate with the investigation, was fined €880m for its part in the cartel.
The truck manufacturers involved were responsible for nine out of 10 of the medium and heavy trucks produced in Europe, the European Commission said.
"As the only UK organisation specifically dedicated to the road haulage industry, we at the RHA considered ourselves duty-bound to pursue a compensation claim for the operators that paid over the odds for their trucks - new, leased or second-hand," the association said.
"Of course this won't happen overnight - it's a long process," it added.
"But we will continue to push for a result that will help the thousands of operators who have been dealt an extremely poor deal."