Latest FCA figures show dramatic increase in suspicious transaction reports since financial crisis

The figures also showed a 24% increase in the number of suspicious transaction reports (STRs) filed between 2013 and 2014. Reports of 'misuse of information', the most frequently reported type of STR, also rose 24% last year - from 1,164 reports in 2013 to 1,451 in 2014, according to the figures.

Financial regulation expert Michael Ruck of Pinsent Masons, the law firm behind Out-Law.com said that the increase did not necessarily mean more wrongdoing by City workers. Rather, the figures suggested that regulated firms and staff had become better at identifying and reporting suspicious activity, he said.

"Over the past two years, the FCA has significantly increased its focus on STRs," he said. "The FCA has carried out – and continues to carry out – supervisory visits to firms to more closely review the systems and controls in place to identify suspicious transactions. This focus has led to a substantial increase in the number of STR reports the FCA has received."

"There is a heightened awareness that turning a blind eye to suspicious activity is no longer acceptable. Personal accountability, the threat of hefty fines and negative publicity is putting pressure on regulated firms and individuals to report suspicious transactions. Whilst firms are often keen to do the right thing, there is also clear motivation for firms and individuals to cover their backs due to the fear of fines, criminal prosecutions and bans now running deep," he said.

A suspicious transaction is one of which there are reasonable grounds to suspect market abuse motives, such as insider dealing or market manipulation. Since the EU's Market Abuse Directive (MAD) came into force in 2005, firms that become aware of suspicious transactions have been required to report them to national regulators for review.

STRs are separated into three broad categories: distortion or manipulation, which accounted for 162 reports in 2014; false and misleading information, which accounted for 13 reports; and misuse of information, which accounted for 1,451 of the reports. Reports of suspected misuse of information have increased by 424% since 2008, the highest percentage increase since the financial crisis, according to the figures.