The U.K.’s financial regulator has issued over £1 billion ($1.35 billion) of fines for regulated firms’ basic internal control failures in the past five years. This accounted for more than half of the total fines issued to financial services firms in the period.

Ruth Prickett graduated from Cambridge University with a BA hons in History and has specialized in business and finance journalism for the past 20 years. She was editor of Financial Management, the magazine...