The poll showed PM Rishi Sunak himself bracing to face a tough challenge in his own constituency of Richmond and Northallerton to Labour.

The poll of over 15,000 people carried out by Survation on behalf of Best for Britain, and put in the field days after the Spring Budget, puts Labour on a 19 point lead over the Conservatives.

This is up 3 points from the campaign group's previous mega-poll conducted at the end of last year, the poll showed.

When the Conservative share of the vote - down to 26% compared to Labour’s 45% - is translated into seats, the poll showed the Tories are on track to win just 98 seats, none of which are in either Wales or Scotland.

This hit to the Tories' electoral prospects comes as Reform UK’s share of the vote surges across the UK, with the party set to come second in 7 seats and their overall vote share up to 8.5%, just behind the Liberal Democrats on 10.4%.

To assess the effect of Reform UK, Best for Britain said it looked at the impact of the party agreeing to ‘stand aside’ for the Conservatives across the UK.

They asked those currently planning to vote Reform UK who they would vote for if the party didn’t stand a candidate in their constituency. In this scenario the Conservatives would win 150 seats - a more than 50% increase in their total seat haul.

Speaking on the Prime Minister's possibility of winning his constituency, the organisation said: "The seat-specific results are particularly damning for the Prime Minister, showing that he is at a risk of losing his own constituency of Richmond and Northallerton to Labour, with Sunak’s lead at less than 2.5% share of the vote."

"The same goes for the Chancellor Jeremy Hunt’s new seat of Godalming and Ash where, despite his efforts to win over voters by cutting National Insurance in the Spring Budget, he is only leading the Liberal Democrats by a 1% share of the vote," the organisation further said in the analyses.

Notably, of those rumoured to be in the race to replace Sunak, only Kemi Badenoch is set to comfortably retain her seat in North West Essex, the analyses said.

Tom Tugendhat and Gillian Keegan are on course to hold their seats, each with a 5% lead over their nearest rivals, while Suella Braverman, Robert Jenrick and Priti Patel’s seats have become marginal, it said.

The poll also suggests that the Conservatives are set to regain four seats lost in recent by-elections.

"These include Chesham and Amersham, where the Lib Dems now slip to third place behind Labour, Glastonbury and Somerton, Honiton and Sidmouth and Tamworth. The data also identifies seven constituencies that are now deemed to be three-way marginals. Best for Britain points out how these losses and close ties highlight the need to provide voters with accurate guidance on how to vote locally, to effect change nationally," the poll said.

Naomi Smith, CEO of Best for Britain, said: “This poll shows we are headed for a change election of unprecedented proportions and major swings as the electorate switches support away from the Tories in different directions."

“Under a first past the post system, and with most voters not knowing who is in second place in their new constituencies, we will be providing voters with state of the art polling analysis at www.getvoting.org to give them the information they need to make sure their vote counts," Smith said.

When was the poll conducted?

The poll of 15,029 adults and MRP analysis by Survation on behalf of Best for Britain was conducted between 8th March and 22nd March 2024.