British insurers have launched an appeal against a Scottish court ruling that threatens to expose them to a raft of asbestos liabilities.

The Court of Session in Edinburgh has upheld the controversial Damages (Asbestos-related Conditions) (Scotland) Act, which allows compensation for the diagnosis of allegedly harmless asbestos-related pleural plaques.

The ruling is a blow to insurers Aviva, Axa, RSA and Zurich, who are fighting the legislation.

Pleural plaques are small fibrous discs on the surface of the lung which indicate exposure to asbestos. Insurers oppose compensation on the grounds the condition is generally harmless and unrelated to the fatal asbestos disease mesothelioma.

The Scottish ruling on pleural plaques contrasts with an earlier House of Lords determination which denied compensation in such cases.

The Association of British Insurers has backed the latest appeal, with Director of General Insurance and Health Nick Starling accusing Scottish lawmakers of ignoring “the well-established legal principle that compensation is payable only when there are physical symptoms”.