The rule changes, which went live in April, gave retirees freedom to take out all of their retirement savings as cash, prompting concern some could fail to invest it wisely.

A study by consultants KPMG in conjunction with trade body the Association of British Insurers, though, showed less than 1 percent of the value of pension funds held by over-55s, and which could theoretically have been withdrawn, actually was.

More than 200,000 Britons have opted to access their pension cash following the introduction of the rules, according to the Financial Conduct Authority.

(Reporting by Simon Jessop; editing by Carolyn Cohn)