The Serious Fraud Office (SFO) has berated Pinsent Masons for "deliberately misinterpreting" data on the number of cases the SFO takes on.

Pinsent Masons has revealed figures that it argues show the SFO is ignoring reports of fraud because of budget constraints.

According to Freedom of Information (FoI) requests carried out by Pinsents, the number of reports to the SFO's dedicated whistleblower email address increased by 324 to 2,832 in 2014-15, but only 16 new investigations were opened.

Pinsents argues that this was because of budget constraints, highlighting the fact that the SFO has recently received an additional £21m from the government to pursue cases.

The firm's head of corporate crime, Barry Vitou, said: "With a whistleblower reporting system in place but not enough money, the SFO will be forced to continue to prioritise only the cases it considers most important, leaving others to fall by the wayside."

However, the SFO has now hit back at the criticism. It said that Pinsents was "deliberately misinterpreting" the data it was given under FoI.

An SFO spokesperson said: "As we have repeatedly pointed out to Pinsent Masons' PR firm, not all frauds fall within the SFO's very specific remit. If the information provided is not for us, we pass it on to other relevant law enforcement agencies and regulators. To suggest the SFO has not been able to investigate is deliberately to misinterpret this data."

"It is also wrong to suggest that the SFO's budget impacts its ability to pursue cases. The SFO will never refuse to take on an investigation on grounds of cost, as demonstrated by its current caseload," the spokesperson said.

The SFO has been under pressure recently after it failed to secure the conviction of six brokers facing charges connected to the LIBOR rate rigging scandal.

In August trader Tom Hayes was sentenced to 14 years in prison for his role in the scandal.