LONDON—Insurers could face asbestos-related claims of about £11 billion ($17.7 billion) in the United Kingdom between 2009 and 2050 as mesothelioma claims rise, an actuarial group says in a revised outlook that more than doubles its previous estimate.

The U.K. Asbestos Working Party, which is part of the London-based association Actuarial Profession, said the updated estimate compares with its 2004 estimate of £4.7 billion ($7.57 billion) in asbestos-related claims. However, the 2004 estimate was for a time period ending in 2040.

In its Tuesday update, the Working Party said it estimates that 90% of future U.K. asbestos claims will be related to mesothelioma.

“The proportion of mesothelioma sufferers that have made a claim for compensation has increased from around one-third in 2004 to nearly two-thirds more recently,” the Working Party said in a statement. “This change, which was not expected in 2004 but has become more evident in recent years, explains most of the increase in total costs.”

In making its estimate, the Working Party said it took into account projections of future deaths from mesothelioma that the U.K. government made last year.

The report is available at www.actuaries.org.uk.