Jeremy Corbyn is seen as a less competent leader than Boris Johnson by voters, The Independent can reveal, as the Labour leader faces questions about his party’s position on Brexit.

Mr Corbyn was regarded as less trustworthy and less capable of managing Brexit than Mr Johnson and his rival Jeremy Hunt, although he was seen as the most able to understand the problems of ordinary people.

An exclusive survey by BMG Research found 19 per cent viewed Mr Corbyn positively, with the overwhelming majority (61 per cent) taking a negative view of his leadership.

Mr Johnson fared better with approval from 29 per cent of voters, but he still face disapproval from 47 per cent of voters, who were asked to state how positive or negative their view was of several senior politicians.

His leadership rival Mr Hunt was also perceived negatively (40 per cent), with just 23 per cent viewing him in a positive light. Theresa May, the outgoing prime minister, also secured support from 23 per cent, while 51 per cent were negative about her leadership.

Cliffs of Dover lit up in Brexit protest Show all 5 1 /5 Cliffs of Dover lit up in Brexit protest Cliffs of Dover lit up in Brexit protest Campaign group Led By Donkeys projected this statement by Nigel Farage on the Cliffs of Dover on the evening of April 4 @ByDonkeys / Twitter Cliffs of Dover lit up in Brexit protest Campaign group Led By Donkeys projected this statement by former Brexit secretary Dominic Raab on the Cliffs of Dover on the evening of April 4 @ByDonkeys / Twitter Cliffs of Dover lit up in Brexit protest Campaign group Led By Donkeys projected this message to the EU on the Cliffs of Dover on the evening of April 4 @ByDonkeys / Twitter Cliffs of Dover lit up in Brexit protest Campaign group Led By Donkeys projected this message on the Cliffs of Dover on the evening of April 4 @ByDonkeys / Twitter Cliffs of Dover lit up in Brexit protest Campaign group Led By Donkeys projected this message on the Cliffs of Dover on the evening of April 4 @ByDonkeys / Twitter

The findings came as a former MI6 chief warned that the UK had been plunged into a “political nervous breakdown” over Brexit, with senior politicians failing to command the respect that prime ministers once held.

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 contenders and Mr Corbyn, who do “not have the standing that we have become used to in our top leadership”.

It also comes as Labour was braced for fresh rows, after it slumped to fourth place in the polls (18 per cent), prompting calls for a change to its Brexit stance.

Dozens of MPs are also facing the threat of deselection under new rules, where the threshold for trigger ballots has been cut to a third of local branches and affiliated unions.

From Monday, MPs have to inform the party if they intend to stand as candidates in the general election, which many believe could come as early as the autumn.

The survey of 1,532 voters found more people thought Mr Johnson was capable of managing Brexit (31 per cent) than Mr Hunt (24 per cent) or Mr Corbyn (15 per cent).

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Mr Hunt, the foreign secretary, was seen as more competent (31 per cent) than Mr Johnson (29 per cent), while Mr Corbyn lagged behind on 18 per cent.

On trustworthiness, Mr Hunt is in the lead on 24 per cent, with his rival on 22 per cent and the Labour leader has 20 per cent.

But Mr Corbyn is seen as the most likely to “understand the problems of people like me” on 24 per cent, with the Conservative leadership candidates neck and neck on 20 per cent.