As the kingmaker who helped put Theresa May into Number 10 in 2016 and then helped keep her there after the disastrous snap election by getting the DUP to formally prop up the prime minister's minority government, Gavin Williamson once reportedly boasted "I made her and I can break her".

But last night she appeared to destroy him.

At a meeting in her Commons office around 5pm, the prime minister told her defence secretary that she believed he was behind the leak of classified information from the National Security Council and asked him to resign. He refused, and was summarily sacked.

"I put to you that latest information from the investigation, which provides compelling evidence suggesting your responsibility for the unauthorised disclosure. No other credible version of events to explain this leak has been identified," she wrote in a letter demanding her leave her government.

She perhaps thought this would be the end of the matter, given that Number 10 decided not to involved the police.


There would be no criminal investigation or prosecution of the cabinet minister who allegedly broke the Official Secrets Act by passing on details of plans to allow Chinese company Huawei to build Britain's 5G mobile network to a national newspaper.

But the prime minister perhaps didn't expect the vociferous response from her defence secretary, who came out on the attack as he swore on his children's lives that he was not source of the leak and accused the cabinet secretary Sir Mark Sedwill of carrying out a politically motivated "witch hunt" against him.

The former defence secretary told me his fate had been decided in "a kangaroo court with a summary execution" and went on to say he had wanted the prime minister to involve the police in the investigation because "I would have been cleared, [because] they would have had to have evidence".

"It would have cleared my name," he said.

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Mr Williamson will have to decide whether he wants to take this any further. But whether you believe him or not, his strenuous denial does raise serious questions for the prime minister and Sir Mark.

If the leak was so grievous, why didn't the cabinet secretary involve the Metropolitan Police in the investigation. And what is the "compelling evidence" that cost Mr Williamson his job. It is actual concrete proof or circumstantial?

Even if Mr Williamson decides not to take it further and retreat to the backbenches without a further fight, Theresa May's opponents are not so willing to let this drop.

Deputy Lib Dem leader Jo Swinson last night wrote to Met Police Commissioner Cressida Dick, asking her to investigate if the leak is a breach of the Official Secrets Act.

Deputy Labour leader Tom Watson also piled in saying Mr Williamson should be prosecuted under the Official Secrets Act and forgo his ministerial severance pay.

But there is also another issue that has perhaps been rather lost in the "whodunnit" saga surrounding the Huawei leak.

Allowing the state-backed Chinese operator in to build the UK's new generation of mobile phone networks is a matter of great national importance and should be debated in public, rather than being nodded through in a secret meeting.

The person who did leak this to Telegraph journalist Steven Swinford presumably lost the argument around the table and felt it important to try to trigger that debate by other means.

The reverberations of this most sensational sacking will be felt for days to come. Not since the Profumo affair of 1963 has a cabinet minister been forced out of their job for a national security breach.

This a devastating fall from grace for an ambitious politician man who went from being a new MP to defence secretary in seven short years and had even harboured hopes that he might one day take the top job.

Now this former chief whip is back where he started in 2010 on the backbenches. This is where his journey ends in the May administration but his brusque sacking on Wednesday night will not be the end of the matter for him.

The prime minister's once powerful ally and backroom operator now an an enemy on her backbenches at the very moment she needs it least. He might seem broken, but does the former confidant of Mrs May have enough to break her too?