After pleading guilty to violating provisions of anti-money laundering rules, U.K. bank National Westminster Bank Plc (NatWest) was hit with a £264.8-million fine.

The sanctions follow the first criminal prosecution for money laundering failings by the U.K.’s Financial Conduct Authority (FCA).

NatWest pleaded guilty and was convicted for three offences of failing to comply with money laundering regulations.

According to the FCA, the charges stemmed from NatWest’s failure to properly monitor the activity of jewellery business Fowler Oldfield between November 2012 to June 2016.

During that time, the company deposited approximately £365 million with the bank, including £264 million in cash.

“Some of the bank’s employees, who were responsible for handling these cash deposits, reported their suspicions to bank staff responsible for investigating suspected money laundering, however no appropriate action was ever taken,” the FCA said.

Following an investigation by West Yorkshire Police, 11 people pleaded guilty to charges relating to the cash deposits and three cash couriers were charged. Another 13 people are awaiting trial in the case. The trial is set for April 2022.

Justice Cockerill, the sentencing judge at Southwark Crown Court, said that while the bank was “in no way complicit” in the money laundering, it was “functionally vital.”

“Without the bank — and without the bank’s failures — the money could not be effectively laundered,” the judge said.

Mark Steward, executive director of enforcement and market oversight at the FCA, said NatWest was responsible for “a catalogue of failures” in how it scrutinised suspicious transactions.

“Combined with serious systems failures, like the treatment of cash deposits as cheques, these failures created an open door for money laundering,” he said in a release.

“We deeply regret that we failed to adequately monitor one of our customers between 2012 and 2016 for the purpose of preventing money laundering,” NatWest CEO Alison Rose said in a statement.

“While today’s hearing brings an end to this case, we will continue to invest significant resources in the ongoing fight against financial crime.”