British deputy prime minister and justice minister Dominic Raab resigned on Friday, following an independent investigation into formal complaints about his behaviour.

Raab has been under a cloud for allegedly victimising his civil servants in three different government departments.

The controversy has dogged Prime Minister Rishi Sunak ever since he succeeded Boris Johnson in October with a pledge to restore "integrity, professionalism and accountability" in government.

Sunak appointed senior employment lawyer Adam Tolley in November to look into two formal complaints levelled at Raab.

More complaints have emerged since from civil servants who worked with the minister, and the Financial Times newspaper quoted one person involved in the investigation as saying it was "devastating".

In a letter to Sunak published on Twitter, Raab said the inquiry had set a dangerous precedent, but that he would remain supportive of the government. (Reuters/AFP)