Penny Mordaunt was forced to deal with a security leak during her time as defense secretary which the department believed came from her predecessor, Gavin Williamson, amid fears the information would put “the life of the our people.”
Three sources told the Guardian that the breach was considered so serious that Mordaunt was prepared to apply for a D-notice to warn any media outlets considering publishing the information that it risked endangering Britain’s national security .
But Williamson, who denied leaking national security information that saw him ousted from cabinet in 2019, said he had nothing to do with the second alleged serious disclosure.
A former government whistleblower said senior MoD officials at the time believed the leak “could only have come from Gavin” and that “our people’s lives were put at risk because of it”.
They declined to discuss the details of the alleged leak, for the same security reasons, but said the issue was a major concern during Mordaunt’s short stint as defense secretary between May and July 2019.
Another source said officials believed “100 per cent” the leak “came directly from Williamson” and that the security services told Mark Sedwill, then the cabinet secretary and national security adviser.
The third source said Mordaunt successfully ensured the leak was contained and the move was never publicly disclosed.
A spokesman for Williamson told the Guardian that the allegation that he was to blame for a second major leak was “categorically false”, adding: “He has no knowledge of it or any involvement with it.”
The Secretary of the Defense and Security Media Advisory Committee can issue D notices to ask the media not to report certain information because it could harm the UK’s national security.
If deemed necessary, the secretary of the committee, who is currently a former army officer, will issue a letter outlining the specific concerns after consultation with the government department concerned. However, it is not mandatory to follow the advice.
A government spokesman said: “We do not comment on matters of national security or alleged leak investigations.” It was also disputed that Williamson had been formally suspected or accused within Whitehall of being responsible for a second significant leak. Mordaunt, who is now leader of the Commons, declined to comment.
Williamson had been sacked by former prime minister Theresa May in May 2019 for leaking details of a contentious national security council discussion on how to manage Chinese phone maker Huawei to the Daily Telegraph. He denied being the source of this leak.
Williamson dramatically resigned on Tuesday night after a series of complaints about bullying and threatening behavior by him when he was a cabinet minister.
A former Ministry of Defense official lodged an official complaint on Tuesday after The Guardian revealed Williamson told them to “cut their throats” in what they said was a sustained campaign of bullying.
It is unclear whether Prime Minister Rishi Sunak was aware of the prior security concern when he appointed Williamson as minister of state in the Cabinet Office.
His short-lived responsibilities included the UK’s Conflict Stability and Security Fund and the Government Communications Service, to which the department’s press officers belong.
A number of ministers, advisers and officials believed Williamson had leaks and tried to truncate stories in the press that contained sensitive classified material, although Williamson himself denied passing on information about Huawei.
A former Downing Street staffer told the Guardian there was “substantial information” proving Williamson was the leaker, and not all of it was made public at the time. “We didn’t want to reveal our methods,” the former employee said.
There was surprise in Downing Street that Williamson so strongly denied being the source – at the time it was reported that he swore on his children’s lives that this was not the case – when No 10 believed he had all the evidence necessary to demonstrate their involvement. .
“The only explanation for his denials at the time was that he wanted to make a comeback,” the former employee said. Williamson was reappointed as education secretary by Boris Johnson but was sacked in a reshuffle before being brought back by Sunak.