Victims of asbestos and their families face more "confusion and uncertainty" after a Court of Appeal ruling.
A leading law firm gave the warning after insurers won a partial victory in a judgment that found only some sufferers could recover damages for the injuries they sustained at work decades ago.
The three judges were unable to agree on a High Court ruling in November 2008 - hailed as a victory for the victims - that employers' insurers at the time of exposure were liable to pay out on claims for mesothelioma caused by exposure to lethal asbestos in the workplace.
Instead, they found that in some cases the responsibility lay with the employers' insurers at the onset of symptoms, which in some cases is 50 or 60 years later.
Lawyer Helen Ashton from Irwin Mitchell, who represented one of the lead claimants in the case, said that although she was delighted the judgment had found in favour of her client, for many people in a similar position this long-awaited, complex judgment would cause more upset and uncertainty.
She said it is now a matter of pot luck as to which victims will be compensated and it will even leave business and insurance companies unsure of where they stand.
Ms Ashton also confirmed that the news received a mixed response from her client Ruth Durham, who had continued the legal battle in memory of her father Leslie Screach, the first person in this litigation to bring a claim.
Mrs Durham said that although her father had died from the fatal lung disease in 2003, after being exposed to the deadly asbestos fibres between 1963 and 1968 while working as a paint sprayer in west London, she had wanted to see justice done for him and other mesothelioma sufferers now and in years to come.
Ms Ashton said: "Without a uniform judgment, it remains unclear which victims are entitled to access the justice they deserve, and it really is pot luck.
"Most tragically, it has added another layer on to what is already a complex claim, meaning that many victims of mesothelioma who have been awaiting the outcome of this appeal decision may not live long enough to know if their families will receive the compensation they need to provide financial security when they are gone."