George Osborne
George Osborne has apparently written the SFO, granting it more cash to fuel its FX fixing probe Reuters

Britain's government is set to grant the Serious Fraud Office additional funding to deal with a "major" criminal investigation into a number of individuals that were allegedly trying to manipulate currency markets.

According to a UK treasury letter, seen by a source that was cited by Reuters, UK Chancellor George Osborne wrote to the SFO, confirming that the Treasury will give the group the money it needs for its extensive probe.

"I understand that the SFO is in the early stages of a major investigation into forex trading. Given the importance of this work, the Treasury will provide the required funding for this investigation," said the letter.

Last month, the SFO requested an additional £26.5m (€33.5m, $42.4m) from the government in a bid to tackle the raft of complex investigations it has under its belt.

On 13 November, the FCA and CFTC fined five banks - Citibank, HSBC, JPM, the Royal Bank of Scotland (RBS) and UBS - a combined total of $3.4bn (£2.1bn, €2.7bn) for their role in the manipulation of the foreign exchange market.

Other authorities have hit a number of these banks with extra penalties.

The Swiss Financial Market Supervisory Authority (Finma) also initiated enforcement proceedings against eleven people involved in the UBS case.