More than 600 Iraqi civilians who allege they were mistreated by British forces have had their damages claims blocked by a Supreme Court ruling.
The claimants alleged they suffered unlawful detention and maltreatment in Iraq between 2003 and 2009 and brought action against the Ministry of Defence.
Iraqi law imposes a three-year limit for claims of this kind to be brought.
The Supreme Court ruled the same limit should apply in an English court, upholding an Appeal Court ruling.
The claims - made by 14 lead claimants representing the group of 600 - were prevented from proceeding in Iraq because the UK armed forces have immunity from legal action there. All the cases were therefore governed in England - albeit under Iraqi law.
But in terms of the time limit for such proceedings, the court said the relevant law was the Foreign Limitation Periods Act. It states that in cases of this type, an English court should "ascertain the relevant rules of the foreign law of limitation and then to apply it to proceedings in England".
A spokesman for Leigh Day, the law firm that represented the Iraqi civilians, said the judgement "creates an additional hurdle for the claimants to overcome in seeking justice for their treatment, but does not of itself deny them access to the UK courts".
He said the High Court was due to hear two test cases against the UK government over its role in Iraq later this year.
"The cases are proceeding and this judgement in no way stops these claims, it just defines the test to be applied to future cases," he said.
But Defence Secretary Michael Fallon said the judgement was a "big step in the right direction" and would "save the taxpayer millions".
"There is a pernicious industry trying to profit from dubious claims lodged against our armed forces years after the alleged incidents," he said.
"Defence spending should go on defence, not into lawyers' pockets."