The value of fines issued by the UK's Financial Conduct Authority has increased nearly fourfold to £577m this year, reaching a six-year high, research by law firm RPC shows.

The increase in the value of fines was largely due to four large fines worth well over £50m issued this year, compared to just one fine over £50m issued last year.

The largest fine of £265m was imposed on NatWest for failing to comply with anti-money laundering measures. HSBC received a £64m fine for a similar reason.

Credit Suisse was also fined nearly £150m for failures in its anti-bribery controls, while Lloyds Bank was fined £90m for treating consumers unfairly in the renewal of their home insurance.

The number of fines also increased by 57% in the last year, from seven to 11.

However, it should be noted that financial penalties are not the sole tool used by the FCA in enforcement, with the regulator able to use a variety of means such as withdrawal of authorisation to prevent businesses engaging in certain activities.

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Jonathan Cary, partner at law firm RPC said: "This year, financial institutions have again been reminded that the FCA will not hesitate to impose sizeable fines - sometimes in the hundreds of millions - for serious failings.

"While the increase in the value of fines is striking, that alone, does not capture the complete picture of the FCA's enforcement activity over the last 12 months. The FCA has a range of other tools it is increasingly prepared to use beyond imposing a major fine. Having permissions withdrawn or varied can be even more serious for a regulated firm.

"While resource does remain an issue, having managed to clear some large cases and with the efforts to rationalise its caseload, the FCA will be looking to ramp up its enforcement activity in the year ahead."