Mrs May’s strongly worded letter to him stated there was “no other, credible version of events” other than to hold him responsible, while Foreign Secretary Jeremy Hunt said she had been left with “no other option”. Labour’s deputy leader Tom Watson swiftly calling for him to be prosecuted, although the PM later said she “considered the matter closed”. A Number 10 spokesman said: “The Prime Minister has this evening asked Gavin Williamson to leave the Government, having lost confidence in his ability to serve in the role of Defence Secretary and as a member of her Cabinet.
“The Prime Minister’s decision has been informed by his conduct surrounding an investigation into the circumstances of the unauthorised disclosure of information from a meeting of the National Security Council.
“The Prime Minister thanks all members of the National Security Council for their full cooperation and candour during the investigation and considers the matter closed.”
The uncharacteristically blunt statement pointedly does not thank Mr Williamson for his time spent in the post.
The inquiry by Cabinet Secretary Sir Mark Sedwill was launched after information from secret discussions about Chinese telecoms firm Huawei’s involvement in the development of the UK’s 5G mobile network was printed in the Daily Telegraph.
Gavin Williamson has been sacked as defence secretary
Last week it emerged that Britain would allow Huawei a restricted role in building parts of its 5G network, seeking a middle way in a bitter dispute between the United States and China over the next generation of communications technology.
The NSC is a forum in which senior cabinet ministers discuss top secret national security information, and the leak, first reported in national newspapers, sparked anger in Parliament.
Mr Williamson was listed in the Telegraph as being among a small group of ministers whose warnings about Huawei’s involvement were overruled by the Prime Minister.
Mrs May’s letter to Mr Williamson
Mrs May’s letter to Mr Williamson, tweeted by Huffington Post journalist Paul Waugh, said: “This is an extremely serious matter, and a deeply disappointing one.
“It is vital for the operation of good government and for the UK’s national interest in some of the most sensitive and important areas that the members of the NSC – from our Armed Forces, our Security and Intelligence Agencies, and the most senior level of Government – are able to have frank and detailed discussions in full confidence that the advice and analysis provided is not discussed or divulged beyond that trusted environment.
“That is why I commissioned the Cabinet Secretary to establish an investigation into the unprecedented leak from the NSC meeting last week, and why I expected everyone connected to it – Ministers and officials alike – to comply with it fully. You undertook to do so.
Theresa May criticised Mr Williamson’s conduct in her letter to him
“I am therefore concerned by the manner in which you have engaged with this investigation. It has been conducted fairly, with the full co-operation of other NSC attendees.
“They have all answered questions, engaged properly, provided as much information as possible to assist with the investigation, and encouraged their staff to do the same.”
In a extraordinary rebuke, she added: “Your conduct has not been of the same standard as others.
“In our meeting this evening, I put to you the latest information from the investigation, which provides compelling evidence suggesting your responsibility for the unauthorised disclosure.
Labour’s Tom Watson said Mr Williamson should be prosecuted if Mrs May was correct
“No other, credible version of events to explain this leak has been identified.”
International Development Secretary Penny Mordaunt has been appointed Defence Secretary in Mr Williamson’s place, Downing Street said.
Questioned as he entered Parliament after the news broke about whether he was responsible for the leak, Mr Williamson responded: “Absolutely not.”
In a subsequent letter, which he tweeted from his personal account, he said: “I am sorry you feel recent leaks from the National Security Council originated in my Department.
Mr Williamson’s response to Mrs May’s letter
“I emphatically believe this was not the case. I strenuously deny that I was in any way involved in this leak and I am confident that a thorough and formal inquiry would have vindicated my position.
“I have always trusted my civil servants, military advisers and staff. I believe the assurances they have given me.”
Mr Watson tweeted: “If he has leaked from the National Security Council, Gavin Williamson should be prosecuted under the Official Secrets Act. And he should forgo his ministerial severance pay.”
Several other MPs called for Mr Williamson to resign his seat, including Liberal Democrat Jamie Stone, who said: “The former Defence Secretary should now fall on his sword and resign as an MP. Gavin Williamson should also be in court for this.
“Any service personnel formerly under his command would face court martial for a similar leak.”
Labour’s shadow Defence Secretary Nia Griffiths said: “The Tories are in chaos and incapable of sorting out their own crisis. Conservative infighting has undermined the basic functioning of government, and has now potentially put security at risk. The police must urgently investigate.”
Asked about the possibility of a prosecution, Theresa May’s official spokesman told a Westminster briefing: “It is not for the Government to determine prosecutions, but the Prime Minister has said, from her point of view, that she considers the matter to be closed.”
Mr Hunt commented: “”On a personal level I’m very sorry about what happened for Gavin’s sake but given the gravity of the situation there was no other alternative outcome.”
Mrs May met Mr Williamson in her Commons office for half an hour after receiving a briefing on the leak inquiry in the early afternoon.
Sky News reporter Kate McCann, citing a conversation with Mr Williamson, said had claimed his sacking was “politically motivated”.
Mr Williamson is the latest in a number of Ministers who backed Brexit in 2016 to leave Mrs May’s cabinet.
Appointed defence secretary in 2017, he is perhaps best known saying Russia should “go away and shut up” in the wave of the Novichok attack on former Russian double agent Sergei Skripal and his daughter Yulia in Salisbury last year.