Liability rates are set to rise by up to 100%, say senior managers.
Royal & SunAlliance liability insurance manager Phil Bell said the current climate in the insurance industry would give insurers a chance to increase rates for liability cover.
"We could be doubling rates for renewals," he said.
Bell said to keep pace with personal injury inflation, premiums should have risen by 76% since 1996. Instead, rates had hardly gone up at all.
St Paul general manager David Bevan agreed rates would have to rise substantially in the new round of renewals. He said: "I can't be more definite on figures but some insureds will find their rates more than doubling."
Bevan added many underwriters were holding off from fixing 1 January renewal rates until reinsurance rates had been set.