Theresa May said members of the National Security Council felt comfortable to “speak as freely as they had done previously” after she dismissed Gavin Williamson as defence secretary for allegedly leaking security discussions.

The former prime minister told a session of Parliament’s National Security Strategy Committee that there was a “slight judder” in confidence among members following the incident.

Mr Williamson was sacked as defence secretary following an inquiry into the leak of information from a National Security Council meeting about Huawei’s involvement in the 5G network.

The Education Secretary, who was appointed to his current position by Prime Minister Boris Johnson some three months later, denied he was the source of the leak.

Mrs May, who also served as home secretary from 2010 to 2016, was asked if the leak had affected how well the National Security Council operated and how long it took to recover.

“I think there was a slight sense initially of concern, particularly obviously from those who weren’t the politicians sitting around the table, about the advice and evidence that they were giving in to the council,” she told the committee.

“Because it had always been the case that the assumption was and it had practically been the case since it was set up that nothing leaked from the National Security Council.

“And it’s really important that nothing leaks from it, because of the nature of the discussions we are having, and you want the agencies, Ministry of Defence and others, who are advising you, to believe and feel confident that they have the freedom to give their best and genuine advice, without feeling that they have got to hold something back.

“So, a slight judder, if you like, when this incident happened, when people were concerned initially, but I think we then got back into the rhythm of people recognising that they could speak as freely as they had done previously.”

Ministers have since declared that technology from Chinese firm Huawei must no longer be used in the UK’s 5G communications network and that existing kit must be stripped out because of security fears.

Mrs May, who ended her turbulent reign as Tory leader in 2019, was also asked to what extent did her government assess long-term strategic issues, such as the UK’s relationship with China.

“We have seen more recently more specific concerns around the human rights issues in China, and of course prior to that around the threat issue of China,” she told the committee.

“The Huawei issue was very live when I was prime minister, continued obviously after I had stepped down. The Government has now taken a decision as to where to go on that, but it was an issue when I was home secretary as well.

“These questions have been there, if you like, in the background I think and being considered. They have come into more public prominence, I would say, in recent years.”

Referring to the publication of the Government’s Integrated Review of foreign and defence policy, Mrs May said that it had tried to strike a “balance” in its view of China.

She said: “It is a major economy, it is a major player on the world stage, we know the way it has reached out across the world. I don’t think we can live in a world where we think we can shut China out in some sense.

“We have to find a way of balancing the relationship with China, which is economic on one side, and then the concerns about security and human rights on the other.”