Boris Johnson’s Conservatives are only eight points ahead of Labour, according to a poll for The Sunday Telegraph.

The ORB International survey for the newspaper puts the Tories on 36 per cent, with 28 for Labour, 14 per cent for the Liberal Democrats and 12 per cent for Nigel Farage’s Brexit Party.

Undertaken on Wednesday and Thursday, the new poll is likely to spark concern within the Conservative campaign.

Experts warned that Mr Johnson will need to significantly increase his lead to be sure of securing a majority.

Four separate election polls conducted in the two weeks before gave the Conservatives a lead of between 13 and 16 points.

Writing in The Sunday Telegraph, Professor Sir John Curtice said that Mr Johnson is behind the vote share achieved by Mrs May at the 2017 election.

He predicts the Prime Minister’s hopes rely in part on winning Labour-held marginals, identifying roughly 50 seats where Mr Corbyn would be vulnerable to a five-point swing to the Conservatives.

The latest poll of 1,510 voters comes after the Prime Minister rejected an offer of an electoral pact with Mr Farage, warning that a vote for the Brexit Party risked gifting Jeremy Corbyn Number 10.

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Mr Farage has promised to field candidates across England, Scotland and Wales if no agreement is formed by November 14.

The ORB poll indicates that among those who voted Remain in the referendum, only 15 per cent will support the Tories, 45 per cent Lab and 25 per cent Liberal Democrat.

It also shows a significant gender difference in Conservative support, with men - 38 per cent - more likely to back Mr Johnson than women - 33 per cent.

Johnny Heald, from ORB International, said: “Boris Johnson has a lead over Jeremy Corbyn but he will need to increase this over the next six week if he wants a comfortable majority in the Commons.”

“Look out also for those who voted remain in 2016.

“At the moment they are 2:1 voting labour over the Lib Dem’s.

“Jo Swinson will need to attract these voters if the party is to mirror gains made in the Euro elections.

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“As we know from 2017 when one of the main stories of the campaign was Labour’s surge half way through, lots will change between now and December 12th.”

The polling showed that the Brexit Party’s strongest age demographic was among 55 to 64-year-olds, 17 per cent of whom indicated they would support the party.

Among 25 to 34-year-olds, 44 per cent said they would vote Labour, compared to 18 per cent Conservative.