The Serious Fraud Office has issued criminal proceedings against three former Barclays traders alleging conspiracy to defraud in connection with its investigation into the manipulation of Libor.
The SFO confirmed that the proceedings involved Jay Vijay Merchant, Alex Julian Pabon, and Ryan Michael Reich, all former employees at Barclays Bank.
They will appear at Westminster Magistrates Court in a few weeks.
The SFO added that the investigation was continuing.
The SFO has been iunvestigating "the Libor matter" since July 2012.
The SFO has already brought charges regarding Libor manipulation against ex-Citi and UBS trader Tom Hayes in June 2013 and RP Martin Holdings' brokers Terry Farr and James Gilmour in July 2013.
More recently, charges were brought against ex-Barclays traders Peter Johnson, Jonathan Mathew and Stylianos Contogoulas in February 2014 and ex-Icap traders Danny Wilkinson, Darrell Read and Colin Goodman in April 2014.
"The Serious Fraud Office continues to work with the UK Financial Conduct Authority and the United States Department of Justice in furtherance of its on-going Libor investigations," it added.
Libor valuations directly influence the value of trillions of dollars of financial deals between banks and other institutions.
The benchmark reference rates are used in euro, US dollar and British sterling over-the-counter interest rate derivatives contracts and exchange-traded interest rate contracts.
Barclays settled with US and UK authorities for £290m in Libor fixing charges in June 2012.