Three former employees at money broker Icap are to face criminal charges brought by the Serious Fraud Office in relation to allegations that they were part of a conspiracy to fix Libor interest rates.

Danny Wilkinson, Darrell Read and Colin Goodman have been told to appear before Westminster court on 15 April when charges against them will be read out. According to the SFO, the offences took place between August 2006 and September 2010. It said they relate to conspiracy charges being brought against former UBS and Citigroup broker Tom Hayes and two former brokers at City firm RP Martin. Hayes and the brokers have pleaded not guilty.

The former UBS broker is accused of conspiring to fix yen Libor with employees at Royal Bank of Scotland, JP Morgan Chase, Deutsche Bank, Rabobank, HSBC and Tullett Prebon, as well as RP Martin and ICAP.

Last September Icap's European business was fined £55m by the Financial Conduct Authority in the UK and the Commodity Futures Trading commission in the US in relation to attempts to manipulate yen Libor.

The three ex-employees were charged six months ago by the US Department of Justice with similar offences, raising questions about tensions between the SFO and US counterparts. Hayes has also been charged in both jurisdictions.

Lawyers for Wilkinson could not be reached, while those acting for Read declined to comment. Goodman's legal representative said his client "strongly asserts his innocence". He added, however, that Goodman "acknowledges that the English courts ... are the correct and appropriate jurisdiction … for the allegations against him to be tried and tested". Last month the SFO brought the first charges in relation to a second alleged Libor fixing cartel. It relates to alleged dollar Libor manipulation between 2005 and 2007.