Which organisation authorises insurers in the UK?

The correct answer is the Prudential Regulation Authority (PRA). This organization is responsible for the regulation and supervision of financial institutions in the UK, including insurers. The PRA operates under the Bank of England and has specific powers and responsibilities that include ensuring the safety and soundness of firms, promoting competition, and protecting policyholders.

The PRA's role is crucial in maintaining the stability of the financial system, and part of this involves granting authorization for insurers to operate within the UK. This ensures that insurers meet the necessary capital requirements and adhere to regulatory standards, which helps in protecting consumers and maintaining confidence in the insurance market.

In contrast, the other organizations mentioned have different roles. The Association of British Insurers is a trade body representing insurance companies but does not have the authority to regulate or authorize insurers. The Department of Trade and Industry focuses on broader trade and economic policies rather than insurance authorization. The Chartered Insurance Institute plays a role in professional education and the development of standards in the insurance industry but does not have regulatory authority over insurers.