Brexit: UK plunged into a 'political nervous breakdown', says former MI6 chief

'It is not surprising that the people who have devoted themselves to serving the interests of this country are concerned about the direction in which the country is going'

The UK has been plunged into a "political nervous breakdown" over Brexit with senior politicians failing to command the respect that prime ministers' once held, a former MI6 chief has said.

In an outspoken intervention, Sir John Sawers said it was "unwise" to hold a referendum in the first place and warned that political turmoil had damaged the UK's standing on the world stage.

The former spymaster said there was anxiety in Whitehall about both the Tory leadership contest and Jeremy Corbyn, who do "not have the standing that we have become used to in our top leadership".

It comes after a row over whether Boris Johnson was cut out of some sensitive intelligence while he was foreign secretary over fears he might inadvertently share secrets.

The leadership frontrunner said it was "not true" that he had been kept in the dark, when pressed on the issue at a leadership hustings on Friday.

Meanwhile, an investigation is under way into leaked concerns from senior civil servants over whether Mr Corbyn was too frail to lead the country.

"We are going through a political nervous breakdown here in the UK," Sir John told BBC Radio 4's Today programme.

"We have potential prime ministers being elected by the Conservative Party now, in the shape of the leader of the opposition, who do not have the standing that we have become used to in our top leadership.

"Whether people can develop that when they become prime minister, we will have to wait and see, in terms of the candidates for the Conservative leadership.

"But I think there is a lot of anxiety, as we leave the European Union we take a huge risk to our international standing, to the strength of the British economy.

"It is not surprising that the people who have devoted themselves to serving the interests of this country are concerned about the direction in which the country is going."

Asked about the reports on Mr Johnson's access to secret briefings, he said: "Intelligence, by its very nature, is carefully handled and distribution is closely guarded, but the foreign secretary would normally be part of that distribution. Normally."

Sir John also argued that David Cameron had been "unwise" to put the decision on EU membership to the British people in 2016.

"That decision now taken, the country is very badly divided, our standing in the world is severely diminished as a consequence of the way in which we are handling all that.

"Can we recover? We recovered after a very messy 1970s with effective leadership in the 1980s.

"So I don't think the situation is irretrievable, but we are going through a very difficult period as a country."

However former Tory leader Iain Duncan Smith, chairman of Mr Johnson's leadership campaign, rebuked Sir John for his comments.

"Actually, I think he might be going through a political nervous breakdown," Mr Duncan Smith said.

"I'm certainly not going through one and I don't think my party is either, to be honest with you.

"The reality is that the expression of democracy may well frighten him slightly."

It comes as a new poll showed Mr Johnson was on course for a landslide victory, with 74 per cent of Tory members saying they would back him in the contest.