In a letter sent to Williamson, British Prime Minister Theresa May accused him of not co-operating with an inquiry set up to determine who had leaked information about Huawei to London's Telegraph newspaper.
May said in her letter, published by Reuters, that the leak was "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, and why I expected everyone connected to it — Ministers and officials alike — to comply with it fully. You undertook to do so," she wrote.
BBC have been told that "more than one concerning issue" had been uncovered regarding Mr Williamson during the leak inquiry and not just the Huawei conversation.— Kevin Beaumont ??♀️ (@GossiTheDog) May 1, 2019
Gavin denies he leaked it.
The Telegraph said that Williamson had denied he was involved in leaking the information. He was also said to have questioned the quality of the investigation into Huawei on which the decision taken by the government had been based.
A few hours after the meeting on 23 April, it was reported that May had decided to allow Huawei to play a role in the rollout of 5G networks in Britain. This is the first time that information has leaked from an NSC meeting.
The story, published by the Telegraph, said it had been decided that the Chinese company could contribute antennas and other infrastructure that are not considered to be part of the core network.
It also said that five ministers — Home Secretary Sajid Javid, Foreign Secretary Jeremy Hunt, Defence Secretary Gavin Williamson, International Trade Secretary Liam Fox and International Development Secretary Penny Mordaunt — had raised concerns about Huawei.
The British Government launched an investigation into the leak and May sent a letter to Williamson on Wednesday, informing him that he had been sacked.
If you’re a government official leaking data to the press, please buy a burner phone and use signal from a busy place with few cameras. pic.twitter.com/IoBygwlN8Y— uɐpʇou@ ✸ (@notdan) May 1, 2019
May's office released the following media statement: "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.
"The prime minister’s decision has been informed by his conduct surrounding an investigation into the circumstances of the unauthorised disclosure of information from a meeting of the National Security Council.
"The prime minister thanks all members of the National Security Council for their full cooperation and candour during the investigation and considers the matter closed."
The UK Department for Digital, Culture, Media and Sport is conducting a review of the country's telecommunications infrastructure.
A public announcement of the UK's policy on 5G suppliers is expected to be made after the DCMS submits its report during the Western spring. iTWire understands that it will not be a binary review about the country from which telecommunications equipment is sourced.