Boris Johnson Getty

Jeremy Corbyn would beat Boris Johnson if the two men were leading their parties in a general election, according to a poll.

When asked who they would prefer as the next prime minister, 29% backed Corbyn, compared with 25% who said Johnson.

The poll comes as the former foreign secretary clashes with May at the Conservative party conference in Birmingham.

The poll also found Labour had taken a 5-point lead over the Conservatives.

LONDON - Boris Johnson is less popular than Jeremy Corbyn and would lose a general election to Labour if he were Conservative leader, according to a new poll.

The poll, carried out by BMG for HuffPost UK, also found that Labour has taken a 5-point lead over the Conservatives as Theresa May's party meets for their annual conference in Birmingham.

Boris Johnson is the public's preferred candidate, should Theresa May step down, according to the poll, with 20% backing his leadership. The next most popular alternative was Jacob Rees-Mogg, on 7%.

However, when asked who they would prefer as the next prime minister, 29% backed Corbyn, compared with 25% who said Johnson. In answer to the same question, May narrowly beats Corbyn by 27% to 25%.

Boris Johnson has been openly critical of the prime minister's Brexit plans since he resigned from Cabinet in July, with talk of him triggering a leadership challenge against the prime minister mounting. On Sunday, he launched his most explicit challenge against the prime minister in a newspaper interview, suggesting her Chequers plan to leave the EU was "deranged."

Johnson told the Sunday Times that "unlike the prime minister I campaigned for Brexit" and suggested that the party could win the next general election if it had a popular leader, as it did when he twice won the London mayoral election.

He also criticised the prime minister's attempts to move the party into the same policy territory as Corbyn's Labour, saying the Conservatives must instead argue for a small state.

Boris's popularity is descending very quickly. I think his behaviour, his comments, his language, his utter disloyalty, is going down really, really badly with the parliamentary party - Conservative MP.

The former Foreign Secretary is to speak at a hotly-anticipated conference rally this week. However, his actions in recent weeks have angered many Conservative MPs, including his former Foreign Office colleague Alan Duncan.

"I think that what he doesn't realise is that whereas he used to be an electoral asset, that is now waning," Duncan told the Times.

One moderate Conservative MP told Business Insider that Johnson's chances of becoming Conservative leader were now "less than 5%."

"I think Boris's popularity is descending very quickly. I think his behaviour, his comments, his language, his utter disloyalty, is going down really, really badly with the parliamentary party," they said.

They added: "I don't think Boris will do it in the end because he will realise he doesn't have the support and it will be embarrassing what poor support he has."

The poll, which surveyed over 1,000 people, was also grim reading for the Prime Minister, with 51% of those polled saying they do not want her to stay in Number 10 until the 2022 general election, compared to 23% who think she should.

Conference bounce?

Jeremy Corbyn Leon Neal/Getty Images

Labour also appeared to have secured a conference bounce from their get-together in Liverpool last week, with the poll indicating a 5-point lead over the Tories following the party's gathering in Liverpool last week.

Labour are on 40% with the Conservatives on 35% and the Liberal Democrats on 12%.

The poll comes as Tory MPs head to Birmingham for their own conference, which launched disastrously on Saturday after a major security flaw in the conference's official app allowed anyone to access the private information of cabinet ministers.

Senior ministers including the Home Secretary Sajid Javid and the Environment Secretary Michael Gove had their private contact details published and altered on the app.

Gove's image was altered to a picture of News Corp boss Rupert Murdoch and Boris Johnson's photo was briefly changed to a hardcore pornographic image

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