Purpose : The purpose of this study is to investigate the major issues and potential effects of the insurance law reform reflected in article 13A of the Insurance Act 2015 in relation to the delay in payment of insurance claim amount by insurers. Research design, data, methodology : In order to achieve the purpose of the study, it is based upon literature research which briefly reviews the background of the UK insurance law's existing position and legal reform on the insurer’s obligation to pay claim amount, focusing on the recently published Law Commission's report and its related previous literatures. Results : There is no doubt that section 13A of the IA 2015 is an advance on the previous law. Nevertheless, the legal analysis of mains issues shows that there still remains a considerable degree of legal uncertainty in respect with the issue on the late payment of insurance claims. The meaning of section 13A is somewhat unclear, and such a matter of uncertainty will be rested on the judgment of English court in the future. Conclusions : Section 13A is not intended to prevent insurers to engage in thorough investigation of losses; it is merely intended to catch some rare examples of bad claims handling. It is therefore expected that cases in which an insurer will be held liable for damages, will be relatively rare, and the effects of law reform will not be so considerable substantially from the perspective with the limit factors under the general law of contract and the practice of English insurance industry.