In March, the regulator banned Paul Robson, also formerly of Rabobank, in its first ever public action against a trader for manipulating LIBOR submissions.

The FCA said the latest ban was “for lacking honesty and integrity” and follows Stewart's guilty plea in March for his role in a conspiracy to manipulate Rabobank’s US Dollar LIBOR submissions. He is due for sentencing in 2017 in the US.

“His behaviour was inexcusable and very serious,” said the FCA's acting director of enforcement and market oversight, Georgina Philippou.

“This ban further reinforces our expectation that individuals and firms take responsibility for ensuring market integrity and reminds them of the consequences if they fall short of our standards.”