Gavin Williamson, U.K. defence secretary, arrives for a weekly meeting of cabinet ministers at number 10 Downing Street in London, U.K., on Tuesday, April 23, 2019.

WASHINGTON — British Prime Minister Theresa May has fired Defense Secretary Gavin Williamson following a leak from a National Security Council of the United Kingdom meeting regarding Chinese tech giant Huawei.

"The Prime Minister has this evening asked Gavin 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," Downing Street said in a statement Wednesday.

In a letter to Williamson, May wrote: "This is an extremely serious matter, and a deeply disappointing one ... That is why I commissioned the Cabinet Secretary to establish an investigation into the unprecedented leak from the NSC meeting last week."

May added that the investigation provided "compelling evidence suggesting your [Williamson] responsibility for the unauthorized disclosure. No other, credible version of events to explain this leak has been identified."

The Daily Telegraph had reported that May approved letting Huawei help build the UK's 5G network, in spite of national security warnings from some of her senior advisors and American officials.

Williamson has denied that he was the source of the leak.

Following Williamson's dismissal, Downing Street announced Penny Mordaunt, the UK's international development secretary, as his replacement. Mordaunt will become the first woman to serve as the UK's defense secretary.