The Serious Fraud Office (SFO) is studying information from global inquiries into the possible manipulation of currency markets.
It is the first sign Britain could follow the US in launching criminal investigation.
The UK is key for multiple probes around the world into the £3trillion-a-day foreign exchange market, partly because about 40% of it is based in London.
Finance industry watchdog the Financial Conduct Authority
(FCA), began its own inquiry into currency markets last year.
Announcing the launch of the Serious Fraud Office investigation, SFO chief David Green said: “The SFO…is receiving and examining complex data on this topic.
“If and when we open a criminal investigation, that decision will be announced in the usual way.”
America’s department of justice launched its own criminal
inquiry last October.
The SFO tends to be late to the party when it comes to global investigations, partly because of a tight annual budget.
The fact material linked to currency exchange has landed on its desk could mean the FCA found evidence of criminal wrongdoing during its inquiries and passed the information on.
The FCA was not immediately available for comment.
Its head of enforcement and financial crime, Tracey McDermott, said just over a month ago she had yet to conclude there had been any misconduct in the foreign exchange market despite trawling through reams of data.
Having launched their own exhaustive internal investigations, banks including Deutsche Bank, Barclays, Citigroup, UBS and HSBC have already fired, suspended or
placed on leave about 40 foreign exchange traders globally.