Former defence secretary Gavin Williamson says he would have been "absolutely exonerated" by a police investigation into the Huawei leak as MPs called for Scotland Yard to launch a criminal probe.
Theresa May sacked Mr Williamson as defence secretary over "compelling evidence" he was responsible for leaking details from a National Security Council meeting to a newspaper - something he "strenuously" denies.
Royal Navy reservist Penny Mordaunt has replaced Mr Williamson, becoming the first ever female Defence Secretary, describing taking the role as an "honour and privilege".
Theresa May's de facto deputy David Lidington said the Government it will "co-operate fully" with any police investigation into the leak.
Scotland Yard said it was not carrying out an inquiry into the leak, although would look into any information "that would suggest criminal offences have been committed".
Mr Lidington and Foreign Secretary Jeremy Hunt stressed it was a matter for police and not politicians to decide whether there should be a criminal investigation.
Pressed on why information was not being passed to the police, a Downing Street source said: "It is not practice in this country for Government to make decisions in relation to prosecutions."
They added: "This was not about what was leaked, it was about where this was leaked from and the importance of maintaining trust and the integrity of the National Security Council."
"I volunteered everything up. I couldn't have volunteered more information on the whole thing," Gavin Williamson 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."
Speaking to the Daily Telegraph, the former minister said he had been "completely screwed".
"She has got the wrong person and the person who did leak this is still out there," he said.
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In a letter to the Prime Minister, Mr Williamson also revealed that he rejected an offer from Mrs May to resign rather than be sacked, saying that this would have sent a signal that he accepted either he or his team was guilty.
In the letter he said: "I am sorry that you feel recent leaks from the National Security Council originated in my department.
"I emphatically believe that 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."
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.
Information shared in the National Security Council meetings are supposed to be held in confidence, with all those who attend required to sign the Official Secrets Act.
Never before has anything been shared from those meetings.
Gavin Williamson last week denied that he or any of his team had divulged any information and has repeated in his resignation letter that that is the case.
In a letter to Mr Williamson confirming his sacking, the Prime Minister said: "This is an extremely serious matter, and a deeply disappointing one.
"The gravity of this issue alone, and its ramifications for the operation of the NSC and the UK's national interest, warrants the serious steps we have taken, and an equally serious response.
"Your conduct has not been of the same standard as others."
A Downing Street spokesperson earlier confirmed the Prime Minister had asked Mr 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."
Penny Mordaunt has been appointed immediately - her successor as Secretary of State for International Development is Rory Stewart, who briefly served as an infantry officer in the Black Watch.
In December, Mr Williamson said he had had an "amazing year" as defence secretary, and on several occasions expressed his belief he had the best job in Government.