But while the ex-minister acknowledges being asked about what happened at the NSC, Williamson insists he told him nothing - and adds that his own admission of the phone call shows that he can not be guilty.
Gavin Williamson was trying to spend a precious few days on holiday with his wife and children in Castle Douglas when there was a knock on his door at 9.30am last Friday.
Whether leaked or not, a decision to allow Huawei to participate in building the country's national 5G infrastructure would create tensions between the United Kingdom and its main ally, the United States.
Huawei denies that its equipment is vulnerable to state espionage.
London's Metropolitan Police force said it was not now investigating, but "if at any stage we receive any information that would suggest criminal offences have been committed, then we will look into that".
UK Prime Minister Theresa May has fired her defence secretary for revealing secret discussions about Huawei Technologies's role in Britain, as she attempted to assert control over a government that has become dominated by the battle to succeed her.
"Clearly, there's been a complete breakdown in discipline and Theresa May needs to take absolutely firm action, and quite frankly I think she needs to call in the police and have a full investigation", said Labour Party defense spokeswoman Nia Griffith.
Labour NEC backs second referendum in specific circumstances
Labour is "the only party which represents both people who supported Leave and Remain", a spokesperson said. Labour will call for a referendum if the Conservatives don't make changes to their Brexit deal.
"It is sitting in the government".
Clearly, if at any stage we receive any information that would suggest criminal offences have been committed, then we will look into that.
He said at the time: "We are keen to find a long-term solution to help all service personnel, from conflicts not only in Northern Ireland but in Afghanistan and Iraq, to ensure that vexatious claims are eliminated".
Williamson was to head back to Wolverhampton to join his family, where he was to consider his next steps.
The move raised questions about whether Williamson's whips' office had a role in preparing the dossier on ministers behind the scandal, and there were reports that Williamson advised May that Fallon may be facing further allegations. "But the evidence was there of a gradual build-up of leaks which started as tittle-tattle after cabinet meetings and gradually built up to serious leaks from NSC meetings".
Labour MP for Wolverhampton South East Pat McFadden, a former Government minister, said: "There are leaks out of the Government".
Rory Stewart, another potential leader but one who has been loyal to May and backs her Brexit deal, replaces Mordaunt as global development secretary.