Downing Street has indicated it could order an inquiry into leaked anonymous warnings that Jeremy Corbyn could be too mentally and physically frail to function as prime minister.

Labour has demanded an independent investigation into claims made in the Times on Saturday, which said senior civil servants had discussed their worries about what may happen if the Labour leader became prime minister.

The report cited anonymous senior civil servants who said they were concerned that Corbyn seemed to lack a firm grasp of issues and was being “propped up” by his advisers.

The shadow Cabinet Office minister, Jon Trickett, raised the leak in parliament on Monday, saying: “I’m standing next to the leader of the opposition, whose fitness I must say is legendary.”

He condemned what he called an “undemocratic and unconstitutional intervention attributed to senior civil servants and based on a falsehood printed in Saturday’s Times”.

Trickett added: “There must be no hesitation at all to condemn the kind of behaviour reported, and I would hope that the government roots out any miscreants or behaviour in this way.”

Asked about the leak, Theresa May’s spokesman said: “Impartiality is one of the fundamental values of the civil service and underpins its ability to effectively serve the government of the day. It would clearly be inappropriate and unacceptable for comments of this sort to have been made or briefed to the press. The cabinet secretary will be writing to the leader of the opposition shortly.”

Asked whether this meant there would be an inquiry, the spokesman said: “I don’t think you’d expect me to divulge the contents of that letter in advance of it being sent.” He said any news on an inquiry would come “shortly”.

Corbyn called for an investigation, saying it was “very concerning” that officials were briefing against an elected politician. Labour has demanded a meeting with Sir Mark Sedwill, whom the party suspects of having direct knowledge of the leak.

Sedwill is a former diplomat who served as Nato’s civilian representative to Afghanistan, where he struck up a close relationship with the US general Stanley McCrystal. Corbyn’s allies believe the motive for the leak was political, based on concerns among securocrats in Whitehall about Labour’s stance on the Middle East.

As cabinet secretary, Sedwill could play a key role in any constitutional wrangle over a no-deal Brexit in the coming months and would be expected to liaise with Labour during a general election, as his predecessor did in 2017.

Labour sources suggested there would be a lack of trust if he could not provide an adequate explanation for where the Times story came from.

One unnamed senior civil servant was quoted as telling the Times: “There is a real worry that the Labour leader isn’t up to the job physically or mentally but is being propped up by those around him. There’s growing concern that he’s too frail and is losing his memory. He’s not in charge of his own party.”

Labour said that Corbyn was due to undergo an operation at Moorfields eye hospital in London for muscle weakness in his right eye, which had been causing him to squint. The party has categorically denied claims he had a minor stroke.

Profile Mark Sedwill: UK's top civil servant Show Sir Mark Sedwill became Britain’s most powerful civil servant in autumn 2018, after it became clear that predecessor Sir Jeremy Heywood was terminally ill. He took the job without having to go through a formal interview process. Already the country’s national security adviser, he had been deputising for Heywood and, having worked with Theresa May for several years, the 54-year-old was someone May felt she could trust. Unlike all but one of his predecessors, Sedwill had never worked at the Treasury, although he holds a masters in economics from Oxford. “Mine is an unusual background for cabinet secretary, having spent much of my career overseas in security and international roles,” he said recently.



Sedwill rose up through the Diplomatic Service, becoming Britain’s ambassador to Afghanistan in 2009 and Nato’s representative in the conflict-ridden country a year later. There were also spells in the Home Office before he became permanent secretary there at what was May’s department in 2013.

Ministerial advisers say his background means he has little patience for leaks, currently running at epidemic rates amid the constant rowing about Brexit. “He just doesn’t understand why anybody would leak, whereas Heywood would see it as an occasional occupational hazard,” one said.



Some even believe Sedwill has been looking for the opportunity to prosecute a leaker, with regular cabinet papers marked secret so they would be covered under the Official Secrets Act, meaning that any leaks could potentially be a criminal offence.



The sharply worded letter he sent to the senior ministers who sit on the National Security Council on 25 April 2019 made clear that immediate cooperation with the forthcoming inquiry was expected. As a result of his investigations, Gavin Williamson was sacked as defence secretary.

Dan Sabbagh, Defence and security editor Photograph: HoC

Civil servants have repeatedly been drawn into the Brexit crisis in recent weeks. The public sector union PCS hit back on Monday after the Tory leadership contender Jeremy Hunt said he would cancel all summer leave for Whitehall civil servants unless they got a letter from their permanent secretary, to prepare for no deal.

The PCS’s general secretary, Mark Serwotka, said: “For a potential prime minister to unilaterally declare that leave for civil servants will be cancelled without consulting them or their union is utterly ludicrous. The government’s handling of Brexit has been shambolic and civil servants have stepped up to the plate on numerous occasions and done their best to prepare for all eventualities.”

The prime minister’s chief Brexit negotiator, Olly Robbins, has signalled that he will leave the civil service, and both leadership contenders have suggested they see a change in the team conducting the talks as one of the keys to unlocking a better deal. Robbins has repeatedly been criticised by Brexiters as a remainer.