The landmark ruling in the pleural plaques test case could lead to hikes in employers' liability (EL) premiums, insurers warned.

But other insurers questioned whether it will have a wider implications for compensation payments.

The High Court judgment handed down on Tuesday ruled in favour of the claimants on liability, but reduced the damages awarded in both partial and final settlement.

The ruling said provisional damages should be between £3,500 and £4,000 and final damages between £6,000 and £7,000. This compares with the £5,000 for provisional damages and £12,000 for final damages that have traditionally been awarded since the 1980s.

Halliwells insurance law partner Victor Rae Reeves, who advised Zurich and Norwich Union on the case said: "The cost saving of such an award, if it stands on appeal, is significant."

The recent asbestos working party paper predicted a medium scenario of some 63,000 pleural plaques and pleural thickening claims to the year 2040, costing £0.86bn.

NU head of technical claims Dominic Clayden warned the ruling could make insurers more cautious and have a knock-on effect on EL premiums. "If this ruling stands, I can see it having an inflationary effect on premiums," he said.

But Zurich said the case did not necessarily set a precedent on compensation for anxiety cases. Zurich and NU are considering an appeal.