A New York judge has dismissed criminal charges against Tom Hayes, the British trader who became the face of the global Libor interest rate scandal.

The former UBS and Citigroup trader served more than five years in prison in Britain for conspiring to rig Libor (London interbank offered rate) - a benchmark used to set rates on trillions of dollars in loans, mortgages and derivatives.

The U.S. decision comes after a separate U.S. ruling in August to throw out convictions for rigging Libor against two former Deutsche Bank traders.

Libor, once dubbed the world’s most important number, was discredited after the 2008 financial crisis when authorities in the United States and Britain found traders had manipulated it to make a profit.

Hayes was released from prison in Britain in January 2021 after serving half an 11-year sentence.

Hayes' legal team is considering further legal options to clear his name, a representative for Hayes said in a statement.

"The U.S. Department of Justice has seen fit to dismiss charges based on the same facts, evidence and case in law that the UK courts used to justify my 11-year prison sentence," Hayes said.

"That alone should be grounds enough for these cases to be referred back to the Court of Appeal in the UK, and if need be to the Supreme Court, which is yet to hear the case."