All U.K. annuity providers are regulated by the Financial Conduct Authority. This means that your annuity is covered by the Financial Services Compensation Scheme (FSCS). If something happened to your annuity provider 90% of your payments would be guaranteed by the FSCS.
In addition, companies will have a Financial Strength rating from an Independent Ratings agency such as Standard and Poor’s or AKG.
The Prudential Regulation Authority will ensure that if the company are to offer a ‘guaranteed’ product, such as an annuity, that the provider has sufficient assets (money and investments) to meet its liabilities (pay your income).