Four former Barclays traders have been sent to prison for manipulating a benchmark interest rate.

Judge Anthony Leonard said Thursday that the fraud committed by Jonathan James Mathew, Jay Vijay Merchant, Alex Pabon and Peter Johnson had hit the "integrity of the market."

The four manipulated the London interbank offered rate, or Libor, between 2005 and 2007. Johnson pleaded guilty to conspiracy to defraud in October 2014. The others were found guilty by a jury last week.

Merchant, described as bearing "the greatest responsibility" for the crime, was sentenced to six and a half years in prison. Mathew and Johnson were both sentenced to four years and Pabon to two years and nine months.

British and American regulators fined Barclays $453 million pounds over Libor fixing in 2012.