Insurers could see their asbestos claims bills slashed if they win another landmark asbestos test case which is due to be heard by the House of Lords next week.
A trio of mesothelioma cases could upset the groundbreaking Fairchild ruling and mean that employers - and their liability insurers - can limit payouts for the deadly cancer.
A recent report by the Institute of Actuaries estimated that asbestos claims would cost the insurance industry £10bn by 2020, with the number of cases peaking at 3,000.
The test cases will determine whether compensation can be split between several employers, reducing the amount a single insurer is liable.
Following the Fairchild judgment, it was found that a single employer could be liable for the full amount of the damages.
Norwich Union is thought to be involved in the case, but was unavailable to comment.
Kieron West, partner with insurance law firm Kennedys, said the mood of judges was changing and that the claimant lawyers were not assured of success. "Judges are now listening far more to both sides of the story. Insurers will be following this case carefully. For too long they have been seen as a big cash cow, but there is less milk left."
Claimant lawyers seized on the case as an attempt by employers to "erode claimants' rights".
James Thompson, partner with John Pickering & Partners, which is representing one claimant, said: "Insurers have an agenda to try to reduce their liabilities as does the employer in the case."
Union law firm Thompsons is also involved in the cases. Ian McFall, head of asbestos litigation said: "The law lords will looking to see if blame can be divided, but we want to make sure that negligent employers pay full compensation - we felt this had already been settled under Fairchild. This is yet another attempt to erode claimants' rights."