Compensation levels were cut by the original ruling

The High Court ruled last month that people with pleural plaques - scarring on the lung lining due to asbestos exposure - could receive compensation.

The firms had said it was not a disease as it had no symptoms.

The potential cost of UK pleural plaque claims could amount to between �200m and �1.4bn over the next 35 years.

Their move came as a claimant in the case challenges his pay-out amount.

'Compensatable condition'

Ellis Hindson, who was awarded �7,000, had applied for damages of nearly �43,000.

Damages of between �5,000 and �15,000 have been awarded to tens of thousands of people with pleural plaques since three High Court rulings in the 1980s made the condition "compensatable".

The High Court case, heard last month, centred on a bid by the two insurance companies to stop pay-outs to people with pleural plaques.

We also have some concerns over the logic of the previous judgement Aviva

The court concluded that anxiety over developing asbestos-related diseases was a valid basis on which compensation could be paid.

But it did reduce the level of compensation that could be awarded in future pay-outs.

'No clarity'

Aviva - which trades as Norwich Union in the UK - said it would appeal because Mr Hindson's latest action showed the previous ruling "has not brought clarity to the issue".

It added: "We also have some concerns over the logic of the previous judgement from a legal perspective and feel the level of damages awarded remain too high".

Zurich said it was appealing after a "close and careful review of the judgement".

Last month's ruling was also made against the UK government, which remains liable for asbestos claims involving the former state-run shipbuilding industry.