Teal Assurance Co Ltd v WR Berkley Insurance (Europe) Ltd and another company [2013] UKSC 57, [2013] All ER (D) 387 (Jul)
Where an insurance had a limit, it made no sense to speak of the insured having causes of action or recoverable claims which together would exceed that limit. If the limit was US$10m and the insured incurred ascertained third party liability of US$10m in respect of each of two successive third party claims, it made no sense to speak of the insured having two causes of action or two recoverable claims against its insurer totalling US$20m.
Likewise, if its liability was ascertained at US$7.5m each claim, the insured would have two causes of action or claims against its insurer, but the second would only be for US$2.5m. The ascertainment, by agreement, judgment or award, of the insured's liability gave rise to the claim under the insurance, which exhausted the insurance either entirely or pro tanto.
Similar considerations governed the incurring of ascertained expenses where those fell potentially within the policy indemnity. An insured could forbear from notifying, or could withdraw or abandon, a claim under