Theresa May sacks Defence Secretary Gavin Williamson over Huawei leak, without due process. Penny Mordaunt, Minister for Women and Equalities, appointed the first Defence Secretary.

Mr Williamson, 42, told friends that he swore on his children’s lives that he was not responsible for the leak and blamed a poor relationship with Sir Mark Sedwill, the cabinet secretary and national security adviser, for his downfall. The two clashed over a cross-Whitehall security review soon after Mr Williamson was appointed defence secretary in December 2017.

The former defence secretary told the Daily Telegraph that he had been “completely screwed” by the outcome of the inquiry. “She has got the wrong person and the person who did leak this is still out there,” he said.

He is said to have admitted speaking to Steve Swinford, the Daily Telegraphjournalist who wrote the story about Huawei, but denied that he had revealed any details of the NSC meeting on April 23. He also insisted that he had helped with the leak inquiry.

“I volunteered everything up. I couldn’t have volunteered more information on the whole thing,” he told The Times. “Frankly I’d rather have had a police inquiry, because the beauty of a police inquiry is I’d have been absolutely exonerated and would have been in the clear.”

He later claimed that the inquiry had been “a witch-hunt from the start” and “a kangaroo court with a summary execution”.

The Cabinet Office launched an unprecedented leak inquiry that required ministers, aides and officials to hand over phones and laptops.

No 10 refused to say whether MI5 or GCHQ had been involved, or to expand on the nature of the evidence pointing to Mr Williamson’s culpability.

Responding to calls led by Tom Watson, Labour’s deputy leader, that the former defence secretary face a criminal investigation, Mrs May’s official spokesman said that she considered the matter now closed. Scotland Yard issued a carefully worded statement making clear that it was up to the Cabinet Office to pass over evidence that would trigger a criminal investigation.

“At this time we’re not carrying out an investigation. Clearly if at any stage we receive any information that would suggest criminal offences have been committed, then we will look into that.”

Some evidence collected in an intrusive inquiry might not be admissible in court.

The Telegraph reported that Mrs May had “overruled” senior ministers and security warnings to allow Huawei permission to take part in Britain’s new 5G mobile internet network.

The US is leading efforts to exclude the company from western government contracts, saying that it poses a security threat.

The final decision on the issue, which pits security and economic interests against one another as well as relations with Beijing and Washington, is one of the most sensitive issues facing the government. The report caused fury in Downing Street and among spy chiefs.

Jeremy Hunt, the foreign secretary, said: “I’m very sorry about what happened for Gavin’s sake but given the gravity of the situation there was no other alternative outcome.”

Lord Dannatt, the former head of the Army, told BBC One’s Breakfast programme that it was “most upsetting for defence”, adding that Mr Williamson had “enemies”, particularly in the Treasury as a result of arguing for more money for the Ministry of Defence, and “maybe they’ve got him”.

Dominic Grieve, Conservative chairman of the intelligence and security committee, backed the prime minister’s decision. He told Sky News: “If people leak the content of the NSC — even if it’s just policy discussions, not some secret item — it undermines the ability of the committee to do its work.”

Other ministers were gleeful about the fall of a former chief whip not afraid to make enemies. “Listen, no one is surprised,” one senior figure said.

The last cabinet minister forced out over a leak was Leon Brittan, later Lord Brittan of Spennithorne, who resigned as Margaret Thatcher’s trade and industry secretary in 1986 during the row over the sale of the Westland helicopter company. His resignation was prompted by the leak of a letter critical of Michael Heseltine.

Frank Gardner, the BBC’s security correspondent, reported that “more than one concerning issue” had been uncovered regarding Mr Williamson during the leak inquiry.

Mr Watson said: “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.”

He added on BBC Radio 4’s Today programme: “The first rule of government is to keep the country safe. If the defence secretary has leaked classified information from the NSC, that requires further investigation.”

Nia Griffith, the shadow defence secretary, said that Mr Williamson’s conduct was “absolutely treacherous”. She told BBC Two’s Newsnight: “I think [Mrs May] needs to call in the police. Clearly, there’s a real breakdown in discipline and Theresa May now needs to take absolutely firm action.

“I think it was absolutely treacherous, both to the country but also to the prime minister. If you are going to run a government, you need loyalty from your ministers, you need loyalty from your cabinet. We have here a case of yet another Tory minister putting leadership ambition before the good of the country.”

Jo Swinson, the Liberal Democrat deputy leader, also wrote to Cressida Dick, the Metropolitan Police commissioner, calling for an official investigation. “I am writing to ask you to open a criminal investigation to ascertain whether the actions of Mr Williamson constitute a breach of the Official Secrets Act,” her letter states.

‘It didn’t take Miss Marple’
There was little sympathy from Gavin Williamson’s former colleagues in government over his sacking, with few expressing surprise at his familiarity with journalists (Matt Chorley writes).

For months members of the cabinet had suspected Mr Williamson to be the source of leaks in the neverending battle of briefing and counterbriefing.

One cabinet minister said within minutes of the announcement: “It didn’t take Miss Marple, did it?”

Another said: “Who would have thought it was him? Apart from everyone who knows him.” A third added: “If he leaked, it is hard to defend a leak like that.”

There was also the suspicion that he valued his relationships with journalists more than those with his fellow ministers. Another texted: “Gavin will be a huge loss to the lobby . . . I mean cabinet.”

Westminster insiders linked Mr Williamson’s fall to his attempts to blame Sir Mark Sedwill, the cabinet secretary, for the leak. “Whoever smelt it dealt it,” said a government aide. “So stupid pointing finger at the cabinet secretary.”

Support came from an unlikely quarter. Damian McBride, a former spin doctor to Gordon Brown who advises Emily Thornberry, the shadow foreign secretary, tweeted that Sir Mark was “out of control”.