Nigel Farage’s Reform UK party is just a point behind the Tories, a new poll released after Rishi Sunak’s manifesto launch shows.
The survey, by YouGov, puts Labour on 38 per cent, with the Tories on 18 per cent, Reform on 17, Lib Dems on 15 and the Greens on 8.
Earlier, Rishi Sunak unveiled pledges on tax cuts as he sought to turn the tide of his disastrous election campaign.
The prime minister promised to cut national insurance by 2p, and scrap it entirely within five years for the self-employed.
Labour hit back at the plans, saying they would lead to higher borrowing, rising interest rates and ultimately “4,800 more on your mortgage”.
The new poll shows the Conservatives have fallen to 18 per cent, down one point on last week.
But Reform is snapping at their heels, going up by one point to 17 per cent.
The survey was carried out throughout Monday and on Tuesday morning, just ahead of the manifesto launch.
Labour is still far in the lead, but has lost three points over the past week.
Earlier, a protester hurled objects at Mr Farage while he was on campaign trail in South Yorkshire, as he waved at supporters from the top of his party’s battle bus in Barnsley town centre.
Mr Farage said he believed the objects were some wet cement from a work site followed by a coffee cup.
Earlier he was at the centre of controversy after he pulled out of a high-profile BBC interview as his party faced a row over whether the UK should have appeased Hitler.
The former Ukip leader was due to take part in a Panorama special with Nick Robinson, set to have been broadcast on Tuesday night.
But it was pulled from the schedule and postponed.
The poll result will further add to the PM’s woes, a day after he was forced to deny he was quitting the race.
At an event at Silverstone, the home of the British Grand Prix, Mr Sunak tried to get his campaign into first gear with plans to cut national insurance, despite fears from his own MPs the move will do little to move the dial.
Around four million self-employed workers would be exempt from the tax under the plans.
Mr Sunak also pledged to “halve migration as we have halved inflation, and then reduce it every single year”.
Mr Sunak also said the Conservatives would deliver 1.6 million new homes, by speeding up planning on brownfield land in inner cities, and ‘scrap defective EU laws’.
He had already pledged not to raise income tax, national insurance or VAT and to introduce a “triple lock plus” to prevent pensioners paying income tax on
The PM said the Tories offered “lower immigration, lower taxes and protected pensions” as part of a “secure future”.
And he warned that if Labour got into power they would change the rules, by giving 16 and 17 year olds the vote, “so that they are in power for a very long time”.