British officials charged former UBS trader Tom Hayes on Tuesday, marking the first prosecution over the Libor rate-rigging scandal that rocked the banking sector last year with repercussions across the world.

"Tom Hayes, a former trader at UBS and Citigroup, has today been charged with offences of conspiracy to defraud in connection with the investigation by the Serious Fraud Office into the manipulation of Libor," the SFO said in a statement.

The government body said that Hayes had been charged by City of London Police at Bishopsgate police station in London with eight counts of conspiracy to defraud.

It was not clear whether the charges related to his time at Swiss bank UBS and/or US rival Citigroup.

In December, British, Swiss and US regulators fined UBS a total of 1.4 billion Swiss francs ($1.5 billion) for having manipulated the Libor Interbank lending rate, which determines a vast number of financial and interest rate contracts around the world.

An SFO spokeman declined to comment on which bank the charges related to, noting that Hayes would appear before London's Westminster Magistrates' Court on Thursday.

The latest twist in the scandal comes after the British Bankers' Association (BBA) last week announced changes to Libor interest-rate transparency in a bid to avoid a repeat of the damaging affair.

The BBA said that publication of banks' individual submissions of the Libor interbank lending rate would be embargoed for three months in a move aimed at avoiding renewed manipulation of the borrowing cost.

It noted that the change, which followed recommendations of a review initiated by the British government, would take effect from July 1.

Reuters