Campaigners were today celebrating a UK Supreme Court ruling that insurance policies cover asbestos-related disease even after employees have left their job.

Insurance companies had sought to limit their obligations to indemnify employers against liabilities towards staff who contracted mesothelioma.

In effect, the ruling is an endorsement of the historical ‘causation’ approach, meaning employers’ liability claims are valid at the time the victim was exposed to asbestos, not when the symptoms appeared.

The ruling could allow thousands of insurance claims by families of people who died after exposure to asbestos.

Today’s decision, by a 4-1 majority, has also been hailed as a victory for employers and current insurers, who will be given certainty over future policies.

In his judgment Lord Clarke said: ‘The whole purpose of these policies was to insure employers against liability to their employees.

‘That purpose would be frustrated if the insurers’ submissions on this point were accepted.’

Len McCluskey, general secretary of the Unite union, said the ‘responsibility holiday’ is now over for insurers.

‘This is a landmark ruling which will affect thousands of victims of asbestos,’ he said. ‘It is a disgrace that insurance companies went to such lengths to shirk their responsibilities.’

Leon Taylor, partner at City firm DLA Piper, said the result will be ‘a relief’ to thousands of disease victims and their families, as well as EL policyholders, whose mesothelioma-related insurance claims have been on hold pending the outcome of the litigation.

He added: ‘For the insolvent insurance companies involved, their administrators and liquidators now have the judicial guidance they needed to satisfy their obligations to properly manage claims in the interests of all the companies' creditors.’

The Association of British Insurers welcomed the ruling and blamed the case on the ‘small group’ of insurers acting independently and at odds with the UK insurance industry.

Nick Starling, ABI director, added: ‘The ABI and our members are committed to paying compensation as quickly as possible to people with mesothelioma who have been exposed to asbestos in the workplace.

‘We have always opposed the attempt to change the basis on which mesothelioma claims should be paid, as argued by those who brought this litigation.’

Click here for the judgment.