Rishi Sunak faces questions about his judgment as Sir Gavin Williamson quit the Cabinet after just a fortnight in office.
The Prime Minister will appear in the Commons to face MPs following the loss of his ally, who stood down after accepting that allegations about his conduct had become “a distraction”.
At Prime Minister’s Questions, Mr Sunak could face pressure to explain why he gave Sir Gavin – who had already been sacked by Theresa May and Boris Johnson – a senior ministerial role despite being aware that he faced an investigation in relation to his behaviour.
Mr Sunak has also faced questions over reappointing Suella Braverman as Home Secretary after she was sacked for breaking ministerial rules by sending a draft official statement to an ally from her personal email.
Labour failed in a Commons bid on Tuesday to release confidential documents showing what the Prime Minister knew about Ms Braverman’s conduct before he reappointed her to the role.
Sir Gavin’s decision to quit as minister without portfolio on Tuesday night followed allegations he sent expletive-laden messages to former chief whip Wendy Morton complaining about being refused an invitation to the Queen’s funeral.
He was also the subject of claims he bullied a former official at the Ministry of Defence and engaged in “unethical and immoral” behaviour while he was chief whip.
Sir Gavin said the allegations against him were “becoming a distraction for the good work this Government is doing for the British people” and was stepping back to “clear my name”.
Late on Tuesday night the outgoing MP also said he will not take severance pay, adding that it should instead go towards other Government “priorities”, such as NHS waiting lists.
“To dispel any speculation, I want to make it clear that I will not be taking any severance,” he tweeted.
“This is taxpayers’ money and it should go instead toward the Government‘s priorities like reducing the NHS’s waiting lists.”
Sir Gavin quit following a meeting with the Prime Minister on Tuesday evening.
In his response, Mr Sunak said he was accepting the resignation “with great sadness” and told Sir Gavin “I would like to thank you for your personal support and loyalty.”
Labour’s deputy leader Angela Rayner suggested Sir Gavin should quit as an MP if he is found to have bullied colleagues or officials.
“There’s no place for bullies in Parliament,” she told BBC’s Newsnight.
She said Mr Sunak appointed Sir Gavin “with full knowledge of serious allegations about his conduct and repeatedly expressed confidence in him”.
“This is yet another example of Rishi Sunak’s poor judgment and weak leadership,” she added.
Liberal Democrat deputy leader Daisy Cooper said: “Rishi Sunak has serious questions to answer about why he appointed Gavin Williamson, then stood by him instead of sacking him.”
Dave Penman, general secretary of the FDA union – which represents senior public servants, said there should be consequences for Sir Gavin if the investigations back up the claims against him.
He added: “Gavin Williamson’s resignation might take some of the political pressure off the Prime Minister, but it mustn’t be a get out of jail free card.
“The allegations against him must still be investigated, and if substantiated, there must be consequences for any future appointment.”
Pressure on Sir Gavin – and questions about Mr Sunak’s decision-making – began with the publication of messages he sent Ms Morton, and the revelation that the Prime Minister was informed of a complaint against him when he appointed his Cabinet.
As well as the internal Tory investigation, she is also understood to have referred the case to Parliament’s bullying process.
In a series of texts peppered with swear words, Sir Gavin accused Ms Morton of seeking to “punish” MPs out of favour with then-premier Liz Truss by excluding them from the Queen’s funeral, warning: “There is a price for everything.”
Another complaint to Parliament’s Independent Complaints and Grievance Scheme (ICGS) has reportedly been made by a former senior official who worked with Sir Gavin when he was at the Ministry of Defence.
He is alleged to have told the official to “slit your throat” and on a separate occasion told them to “jump out of the window”, according to a Guardian report.
On Tuesday night, former deputy chief whip Anne Milton alleged Sir Gavin used intimidatory and threatening tactics while he was chief whip in 2016-17.
She accused him of seeking to use an MP’s financial situation as leverage against them and sending an expletive-laden email about a female civil servant.
Ms Milton described his behaviour as “unethical and immoral” and told Channel 4: “I think he feels that he’s Francis Urquhart from House Of Cards.”
Sir Gavin is a divisive figure at Westminster, where he is viewed with suspicion by many Tory MPs because of his reputation as an inveterate plotter.
He was sacked first by Mrs May as defence secretary in 2019 for leaking details of a National Security Council meeting, and then by Mr Johnson as education secretary over the Covid-19 A-levels debacle.
