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Thanks for joining us for reaction to the sacking of Gavin Williamson as defence secretary - that's where we will leave our live updates for this evening.

His departure follows an inquiry into a leak from a top-level National Security Council meeting, over a plan to allow Huawei limited access to help build the UK's new 5G network.

He has been replaced by Penny Mordaunt, who will become the UK's first female defence secretary.

Mr Williamson has "strenuously" denied leaking information from the meeting, but the PM said "no other credible version of events" has been found to explain the leak.

Labour's deputy leader Tom Watson and Liberal Democrat leader Sir Vince Cable have both said they think the police should get involved in the matter.

But Scotland Yard said in a statement that it was a matter for the National Security Council and the Cabinet Office, and it was not carrying out an investigation.

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Gavin Williamson’s denial over being behind the leak from a top-level National Security Council meeting is “extraordinary”, a security think tank says.

Prof Michael Clarke, from the Royal United Services Institute, says Mr Williamson has implied that the investigation was “not formal or thorough” which is a direct criticism of those who conducted the inquiry.

He adds: “Gavin Williamson is going down fighting and he’s maintaining, in effect, that they’ve got the wrong man.

“That’s extraordinary – for a senior minister to be in that position.”

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Liberal Democrat leader Sir Vince Cable says Gavin Williamson's sacking is "absolutely extraordinary".

He says he agrees with Labour deputy leader Tom Watson that "this is clearly a police matter".

"The Metropolitan Police are going to have to get involved as quickly as possible".

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Penny Mordaunt says she is "delighted" to have been appointed defence secretary following the sacking of Gavin Williamson.

Ms Mordaunt, who becomes the first woman to take the role, said: "I'm delighted to be back at the Ministry of Defence.

"It is an honour and privilege to work with the best armed forces and defence civilians in the world."

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New International Development Secretary Rory Stewart says he believes the prime minister "made the right decision" in sacking Gavin Williamson.

He said he had known National Security Adviser Mark Sedwill "for many years" and has "full confidence in that investigation".

He added: "I have a lot of confidence in the process he will have conducted. I have a lot of confidence in the prime minister and I'm sure that they made the right decision."

On his new role, he said: "I'm absolutely delighted. Personally for me I've spent a lot of my life working abroad... It's a chance to engage in some of the most pressing issues in the world."

Liberal Democrat deputy leader Jo Swinson has asked the police to open an investigation into whether Gavin Williamson breached the Official Secrets Act.

In a letter to the Metropolitan Police Commissioner Cressida Dick, she wrote that she wanted an investigation "given that the leak originated from the National Security Council and related to highly-sensitive information".

The letter was also signed by Lib Dem leader Sir Vince Cable and MP Sir Ed Davey.

Laura Kuenssberg
BBC political editor

Downing Street has made a very serious accusation and is sure enough to carry out this sacking.

For the prime minister's allies, it will show that she is, despite the political turmoil, still strong enough to move some of her ministers around - to hire and fire.

Mr Williamson is strenuously still denying that the leak was anything to do with him at all.

There is nothing fond, or anything conciliatory, in either the letter from the prime minister to him, or his reply back to her.

Read more here.

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Foreign Secretary Jeremy Hunt says the prime minister had no alternative but to sack Gavin Williamson as defence secretary.

Speaking as he arrived in Addis Ababa, Ethiopia, Mr Hunt said: "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."

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Labour’s deputy leader Tom Watson has called for a police inquiry to investigate whether or not Gavin Williamson breached the Official Secrets Act.

“It’s the most brutal sacking letter of any minister I’ve seen in my lifetime” he said.

“The magnitude of the allegation against him is very serious.”

He said that it was a crime to breach the Official Secrets Act, but acknowledged that Mr Williamson strenuously denies the allegation.

“He denies it – he deserves to have his voice heard.”

The way to do that is to hold a “criminal inquiry” he added, which he said he believed should “go ahead rapidly.”

Scotland Yard says it is not carrying out an investigation into the leak from a top-level National Security Council meeting.

In a statement, it said: "We're aware of the media reports in relation to the leak and that is a matter for the National Security Council and the Cabinet Office to look at.

"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."

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Penny Mordaunt's appointment as the new defence secretary follows a term serving as the International Development Secretary.

Ms Mordant has a background as a naval reservist and previously served as the armed forces minister under David Cameron.

The daughter of a paratrooper and a special needs teacher, she is probably best known outside Westminster for her appearance on ITV's celebrity diving show Splash! to raise money for charity.

She campaigned for a Leave vote in the 2016 EU referendum.

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Downing Street has played down talk of a possible prosecution over the leak from a top-level National Security Council meeting.

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."

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.

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Speaking to the BBC, Commons Defence Committee chairman Julian Lewis says that Gavin Williamson’s sacking as defence secretary is a “loss” when looked at “purely” from the point of view of defence.

“He has been good for defence", the Conservative MP adds.

However he says that “it probably is inevitable that if someone is caught bang to rights leaking from any cabinet committee” then “it’s a career-destroying moment".

He says he thinks “very highly” of Williamson’s replacement, Penny Mordaunt.

“She will bring a great deal of talent and ability to the job."

The National Security Council is made up of senior cabinet ministers and its weekly meetings are chaired by the prime minister, with other ministers, officials and senior figures from the armed forces and intelligence agencies invited when needed.

It is a forum where secret intelligence can be shared by GCHQ, MI6 and MI5 with ministers, all of whom are bound by the Official Secrets Act.