The unprecedented leak of talks involving senior ministers and spy chiefs on the involvement of the Chinese tech giant Huawei in the UK’s 5G network has caused anger and dismay in Whitehall.
While unauthorised leaks of Cabinet discussions on Brexit have become commonplace in recent months, the deliberations of the National Security Council (NSC) have remained watertight.
So when the Daily Telegraph reported the NSC had agreed that Huawei should be allowed a limited role in building the 5G network there was concern the body dealing with some of the most sensitive matters in government had been compromised.
MPs were quick to link the disclosure to manoeuvrings at Westminster by senior Tories to position themselves for a leadership run when Theresa May steps down – or is forced out by her turbulent party.
Ten members of the Cabinet attend NSC meetings – which are chaired by the Prime Minister – together with National Security Adviser Sir Mark Sedwill, his two deputies, and the heads of MI5, MI6 and GCHQ.
The Telegraph report suggested five of the ministers – Sajid Javid, Jeremy Hunt, Gavin Williamson, Liam Fox and Penny Mordaunt – had voiced misgivings about the Huawei decision.
It prompted suggestions that whoever was responsible for the leak was trying to make themselves look tough on China, knowing that many Conservative MPs harbour concerns about Chinese involvement in the UK’s critical national infrastructure.
Mr Javid, the Home Secretary, and Mr Hunt, the Foreign Secretary, have long been seen as potential candidates in any leadership contest.
However Defence Secretary Mr Williamson is also reported to nurse ambitions for the top job.
The former chief whip was said to have been angered by a report last year claiming he had been overheard plotting against Mr Javid and Mr Hunt while discussing his own prospects of succeeding Mrs May.
He caused consternation with a speech in February when he announced his intention to send the Royal Navy’s new aircraft carrier HMS Queen Elizabeth to the Pacific to challenge Chinese territorial ambitions.
His intervention infuriated the Chinese, resulting in the cancellation of a planned visit to Beijing by Chancellor Philip Hammond.
Dominic Grieve, chairman of the parliamentary Intelligence and Security Committee, said the leak of the NSC discussions was “deeply worrying” and that if any minister was found to be responsible they should be sacked.
He said collective Cabinet responsibility appeared to be breaking down and acknowledged it could be linked to the manoeuvrings around the Conservative leadership.
“The principle that what is discussed at the NSC is kept totally confidential is really important,” he told the BBC.
“The problem that we have at the moment is that collective Cabinet responsibility has been breaking down and we have seen plenty of leaks come out of Cabinet meetings.
“There has certainly been some posturing around on a whole range of issues. I can’t pretend that there aren’t people who appear to be preparing themselves for leadership bids. None of this is in the national interest, in my view.”