Sunak defended giving Williamson a seat at the Cabinet table, saying he was not aware of "any of the specific concerns" about Williamson's past conduct.

Opposition leader Sir Keir Starmer accused Sunak of hiding behind bullies because he's "too weak" to take them on, saying Sunak gave Williamson a job "precisely" because he's a bully.

Williamson, who was appointed the Minister without Portfolio two weeks ago, resigned on Tuesday saying the allegations had "become a distraction" from the government's "good work."

He also said he refutes "the characterisation of these claims" and that he will comply with the parliamentary investigation process and clear his name.

In a separate Twitter post, Williamson said he will not take severance payment.