Britain's Financial Services Authority (FSA) warned on November 15, that criminal groups are increasingly laundering money and stealing from financial firms by planting people as staff.
"There is increasing evidence that organised criminal groups are placing their own people in financial services firms so that they can increase their knowledge of firms' systems and controls and thus learn how to circumvent them to commit their frauds," FSA Chairman Callum McCarthy told the regulator's financial crime conference.
Fraud costs the UK around 14 billion pounds ($24.25 billion) a year, or 230 pounds per person, and it is estimated that 25 billion pounds of dirty money is laundered through British financial institutions every year.
The FSA, the government and British law officers are working more closely to tackle fraud and last month the government launched a review to establish a national fraud strategy.
The FSA is also looking at how companies deal with fraud and will publish a report early next year.
Recently, the FSA fined the emerging market bond broker Investment Services UK (ISUK) and its director more than 200,000 pounds for failing to implement adequate anti-money laundering controls on clients.