The first trial relating to the Libor rate rigging scandal will begin today in London. 

Tom Hayes, 35, a former star trader at UBS and Citigroup, will face charges of conspiracy to rig the Libor benchmark interest rate, which affects $450tn worth of borrowings. 

The seven year-long enquiry which has led to charges against Hayes and 21 others has already resulted in payouts of $9bn by banks and brokerages found to have been involved.

The Serious Fraud Office (SFO) has charged Hayes, a former yen derivatives trader, with eight counts of conspiracy to defraud between 2006 and 2010. The charge carries a maximum sentence of ten years. He has pleaded not guilty.

The SFO alleges Hayes conspired with workers from UBS, JP Morgan, Citigroup, RBS, Deutsche Bank, Rabobank and HSBC.

Libor is calculated by a system in which banks report their estimated costs of borrowing from each other in various currencies over various borrowing periods. Oversight of the system, by the British Bankers' Association at the time, was lax and non-transparent.

The SFO's legal team will attempt to prove that Hayes made "dishonest" submissions to benefit his own trading book.

According to RTE, the trial at London's Southwark Crown Court is expected to last between 10 and 12 weeks.