The Serious Fraud Office has charged three former employees at Barclays traders, Peter Charles Johnson, Jonathan James Mathew, and Stylianos Contogoulas in connection to the manipulation of one of the world's most important lending rates – Libor.
In a statement, the SFO said It is alleged they conspired to defraud between 1 June 2005 and 31 August 2007.
On 6 July 2012, the SFO announced that it had decided to accept the Libor case for investigation after Barclays was the first to settle with UK and US authorities the month before for £290m (€341m, $448m) for try to rig Libor.
In mid-January this year, the SFO ordered several former Barclays traders for interviews after suspecting them of manipulating some of the world's important interbank lending rates.
At the time, it sent notices to the unnamed traders to be interviewed under caution over their suspected involvement in Libor fixing.
The SFO can conduct three types of interviews; compulsory, under-caution and voluntary. Under UK law, an interview under caution can lead to the SFO using anything the suspect says as evidence in a criminal trial.
The SFO can seek an arrest warrant if the suspects do not turn up to the interview.
Meanwhile, ten people have been charged with allegations, under US and UK investigations, into benchmark interest rate fixing.
Former UBS and Citigroup trader Tom Hayes and two former RP Martin brokers Terry Farr and James Gilmour appeared at a plea hearing on 17 December in the UK and plead not guilty.
The three are the first to face trial under the SFO's probe into Libor manipulation since the scandal broke out in 2012.