The UK Supreme Court has made a ruling which could allow thousands of insurance claims by families of people who died after exposure to asbestos.
The court placed insurance liability at the time an employee was exposed to asbestos, not when symptoms appeared.
Relatives of workers who died of the cancer mesothelioma want to make claims on policies dating from the 1940s.
One insurance firm in the case said the ruling was not its “favoured outcome” but welcomed the clarity it brought.
The Association of British Insurers welcomed the ruling, and blamed a small group of insurers for the legal battle.
The Supreme Court was asked to rule on the issue after judges in lower courts failed to agree.
Families had a success in 2008, when the High Court said firms’ insurers at the time workers inhaled fibres were liable.
But two years later the Court of Appeal said that in some cases liability was triggered when symptoms developed - which could be decades after exposure.
Lawyers said the appeal court ruling had left victims’ families facing “confusion and uncertainty”.
The new ruling by a panel of five Supreme Court justices states that the disease can be said to have been “sustained” by an employee in the period when it was caused or initiated.