Three former Barclays bankers have been charged "in connection with the manipulation of Libor" interest rates, the Serious Fraud Office said.
The SFO alleges the three – Peter Charles Johnson, Jonathan James Mathew and Stylianos Contogoulas – "conspired to defraud between 1 June 2005 and 31 August 2007".
They will appear at Westminster Magistrates court at a date to be confirmed.
The fraud-busting agency has been investigating the Libor affair – that has seen banks paying out hundreds of millions in pounds in fines to regulators on both sides of the Atlantic – since July 2012.
It has already launched prosecutions against former UBS banker Tom Hayes along with Terry Farr and James Gilmour, who worked for money broker RP Martin. They have all denied its charges of fraud.
The SFO said yesterday that it "continues to work collaboratively with the UK Financial Conduct Authority and the US Department of Justice on their respective ongoing investigations" into the affair.
Barclays was the first bank to be penalised over the alleged involvement of its traders in attempts to manipulate the interest rate. It agreed to pay £290m in total in the same year the SFO became involved.
The fine and revelations which followed sparked an unprecedented wave of public anger, and cost both the chief executive Bob Diamond and chairman Marcus Agius their jobs. However, that was only the start of it. UBS paid out close to £1bn and Royal Bank of Scotland £390m. European watchdogs then got in on the act, tabling penalties of their own.
Libor is determined by banks on a panel submitting what they expect to pay to borrow from other banks, although the process is now being reformed. The interest rate derived from this is used to price a huge range of financial transactions.
Separate rates are set for a variety of currencies. Another rate, Euribor, is collated from banks in the eurozone.
Last month, three former traders at Dutch bank Rabobank were charged in the US over allegedly conspiring to manipulate the yen Libor benchmark interest rate since 2006. If convicted, they could face up to 30 years in prison.