Workers diagnosed with a particular asbestos-related condition will no longer be able to claim compensation, law lords ruled today.
Union leaders and lawyers for claimants have attacked the House of Lords decision to end claims for pleural plaques - a condition which causes the thickening of lung membranes in those who have it.
They say the decision that the "thousands" of people in the UK diagnosed with pleural plaques will no longer be able to seek compensation for the condition, which has been linked to exposure to asbestos.
Pleural plaques can, but do not always, develop into fatal diseases such as asbestosis and mesothelioma - a cancer for which there is no cure.
But lawyers for those diagnosed with pleural plaques had argued that their clients should be entitled to sue for compensation for anxiety caused by the condition, with the Unite union claiming that such a diagnosis can lead to "extreme distress" for victims.
However law lords today rejected an appeal brought by the union against an earlier ruling by the Court of Appeal in January 2006, when the lower court decided that sufferers of pleural plaques shouldn't receive compensation.
Reaching the decision the law lords ruled that pleural plaques was not a disease.
Unite said the ruling removed an automatic right to compensation that had been in existence for 20 years, claiming that the decision would result in "massive savings" for the insurers of companies accused of exposing their employees to asbestos.
"This is a harsh decision which will affect thousands of people with pleural plaques now and in the future," said Unite joint general secretary Derek Simpson.
Ian McFall, head of asbestos policy at Thompsons Solicitors - who ran the case on behalf of Unite - added: "This decision is very disappointing for the thousands of people who are living with the worry of knowing that their lungs have been scarred by asbestos.
"They will be baffled and offended that the House of Lords has decided that pleural plaques is not worthy of any compensation."
A spokesman for Norwich Union, which had been involved in claims for pleural plaques, said the insurer welcomed the ruling for the "clarity" it brought over the issue. He added that the law lords had seen fit to rule that the "worried well" should not be compensated.