The rule of warranty in English insurance law was established in the second part of the $18^{th}$ century by Lord Mansfield, who laid the foundations of the modern English law of insurance contract and developed very different rule of insurance law, especially in the field of warranty. At the time of Lord Mansfield, warranty, that is, the promise given by the assured, played an important role for the insurer to assess the scope of the risk. Legal environments, however, have changed since the age of Lord Mansfield. English and Scottish Commissions proposed very dramatic reform of law in the field of warranty law to reflect the changes of legal environment through the Insurance Act 2016. This article intends to consider the legal implications through the comparative analysis between the new regime of warranty in the Insurance Act 2015 and MIA 1906. The major changes in the Insurance Act 2015 are summarized as following. First, Basis of the contract clauses in non-consumer insurance contracts should be of no effect and representations should not be capable of being converted into warranties by means of a policy term or statement on the proposal form. This requirement should not be capable of being avoided by the use of a contract term and the arrangement of contracting out by parties should be of no effect. Secondly, The existing remedy for breach of warranty, that is, automatic discharge of the insurer's liability, should be removed. Instead, the insurer's libility should be suspended from the point of breach of warranty and reattach if and when a breach of warranty has been remedies. Thirdly, A breach of warranty should genally be regarded as remedied where the insured ceases to be in breach of it. In the other hand, for time-specific warranties which apply at or by an ascertainable time, a breach should be regarded as remedies, if the risk to which the warranty relates later, becomes essentially the same as that originally contemplated by the parties. Fourthly, where a term of an insurance contract relates to a particular kind of loss, or loss at a particular location/time, the breach of that term should only give the remedy in relation to loss of that particular kind of loss, or at a particular location/time. Finally, whether a term of an insurance contrat relates to loss of a particular kind of at a particular location/time should be determined objectively, based on whether compliance with that ther would tend to reduce the risk of the occurrence of that category of loss.