Financial Services Authority - FSA
Once upon a time, the Financial Services Authority was the key financial regulator in the U.K. It developed from the Securities and Investments Board, a body founded in the 1980s. In the early 2000s, it was given additional powers and its name was changed to the FSA, with broad oversight over the financial industry. Its responsibility included regulation of banks, insurance companies, and investment firms.
Following the financial crisis of 2008, the U.K. government thought that increased oversight of the financial industry might be prudent (a little "closing the barn door after the horse escapes," but better late than never). As a result of a process that began in mid-2010, the British government disbanded the FSA, with the final nail going into the coffin in 2013.
The responsibilities the authority once held were split between two agencies. The Financial Conduct Authority took over regulation of financial firms with product lines aimed at consumers. Meanwhile, the Prudential Regulation Authority became the body responsible for oversight of banks, investment firms, and insurance companies.