Budget cuts are stifling attempts by the City of London Police to crack down on incidents of money laundering, raising fears that crimes could be going undetected, according to a top accountancy firm.

Although there has been a small rise in the number of money laundering investigations by the department, cutbacks continue to keep the numbers low, research by Moore Stephens, a major accountancy firm, shows.

The firm says the number of investigations into money laundering by the City of London Police rose to 23 in 2015 from 15 in 2014, with just 104 money laundering cases opened in the last five years. Now there are concerns that some crimes “could be slipping through the net”.

According to the City of London Police, its budget has been cut by 15 per cent over the last five years to just £121.6m in 2014-15.

The City of London Police works with the Serious Fraud Office on fraud cases, and plays a central role in investigating money laundering and other financial crimes.

John Baker, anti-fraud director at Moore Stephens, said: “It is concerning that the number of investigations into money laundering is so low. The City of London Police is one of the only forces in the UK to have fraud in its top-ten priorities, and it is imperative that it gets proper funding for that task.”

The City of London is regularly hit by money laundering allegations, the latest being the “Global Laundromat” scandal, in which nearly $740m (£568m) in laundered Russian money reportedly went through the UK banking system.

In March, the Government announced it was to set up a new watchdog to close loopholes used by criminals as part of a wider clampdown on money laundering and terrorist financing.