A British prosecutor says a former Citibank and UBS trader motivated by greed served as the ringmaster of the alleged manipulation of a key interest rate, the London Interbank Lending Rate, or Libor.

The charges against trader Tom Hayes, who specialized in products pegged to yen-denominated Libor, relate to the period from August 2006 to September 2010. He is charged with conspiring with employees from other leading institutions.

Prosecutor Mukul Chawla says the 35-year-old Hayes' greed "led to his dishonesty on an enormous scale."

Libor is a key rate that banks use to borrow from each other. Indirectly, the rate affects what people pay when they take out loans, such as a car loan.

Hayes denies all eight charges in the case that opened Tuesday at Southwark Crown Court.