Rishi Sunak has suffering his first serious political embarrassment since becoming Prime Minister on October 25 with the resignation of a cabinet minister who was accused of sending expletive ridden messages to a woman colleague and telling a civil servant to “slit your throat”.

While Rishi cannot be held responsible for the personal behaviour of Gavin Williamson, the Prime Minister’s judgement is being called into question in appointing such a controversial politician a minister of state (minister without portfolio) at the all important Cabinet Office.

Many will recall that in an earlier job, when Williamson was chief whip in charge of ensuring discipline among Tory MPs, he was understood to have kept a pet tarantula, named Cronus, on his office desk.

Labour said that Sunak had shown “poor judgment and weak leadership”, a charge repeated by Keir Starmer, the opposition leader, at Prime Minister’s Questions on Wednesday.

The headlines following Williamson’s resignation late on Monday night say it all.

“Williamson quits over bullying allegations,” reported the Daily Telegraph, adding, “Minister’s resignation piles pressure on Sunak to explain why he was appointed.”

They are not very different in the Times, one of the few papers which had endorsed Rishi against Liz Truss in the Tory leadership contest.

“Rishi Sunak is facing questions about his judgment after Sir Gavin Williamson quit the government over allegations of bullying just two weeks after the prime minister took office,” the Times summed up.

The cabinet office minister said that he had become a “distraction” for the government as he faced two formal investigations.

Williamson’s departure — the third time he has left government in three years — “will raise questions about Sunak’s decision to appoint him in the first place,” the Times added.

“His position became unsustainable after a former senior civil servant made a formal complaint about claims that Williamson had told him to ‘slit your throat’ and ‘jump out of a window’.

“Williamson already faced a separate investigation after he sent expletive-laden text messages to a former chief whip over claims that he had been excluded from attending the Queen’s funeral.”

According to the messages published by the Sunday Times, Williamson accused the then chief whip Wendy Morton of exploiting the Queen’s death for political purposes. Williamson was not among the privy councillors invited to the Queen’s funeral.

He told her that it was “very poor and sends a very clear message” that members of the Privy Council, including him, who were not “favoured” by Truss, were being deliberately excluded.

When Morton insisted it was “not the case” that political opponents were being excluded, Williamson replied that it looked “very shit”.

He added: “Also don’t forget I know how this works so don’t puss (sic) me about.” Williamson served as chief whip himself under Theresa May’s premiership.

“It’s very clear how you are going to treat a number of us which is very stupid and you are showing f**k all interest in pulling things together,” the messages read. “Don’t bother asking anything from me.”

Another read: “Well let’s see how many more times you f**k us all over. There is a price for everything.”

Rishi was told about the messages but still included Williamson in his cabinet. The Prime Minister will face further pressure about reappointing Suella Braverman as home secretary a week after she had resigned.

In his resignation letter Williamson said: “As you know there is an ongoing complaints process concerning text messages I sent to a colleague. I am complying with this process and have apologised to the recipient for those messages.

“Since then there have been other allegations made about my past conduct. I refute the characterisation of these claims, but I recognise these are becoming a distraction for the good work this government is doing for the British people.

“I have therefore decided to step back from government so I can comply fully with the complaints process that is under way and clear my name of wrongdoing.”

Sunak responded: “It is with great sadness that I accept your resignation. I know your commitment to successive Conservative governments and the party over the years has been unwavering. I support your decision to step back and understand why you have taken it. I would like to thank you for your personal support and loyalty.”

The Guardian, which backs Labour and believes there should be a general election to oust Rishi and the Tories from power after 12 years in government, listed Williamson’s very long list of “gaffes, scandals and controversies”.