Support for Britain's ruling Conservatives has plunged to a level last seen during former leader Liz Truss's brief premiership, according to a YouGov poll released Thursday.

The survey comes as beleaguered Prime Minister Rishi Sunak endures speculation in UK media that Tory MPs will try to oust him before a general election due this year.

YouGov put the Conservatives on 19 percent -- the same vote share as Truss at her lowest ebb in 2022 after her disastrous mini-budget spooked financial markets and sank the pound.

The poll of more than 2,000 adults, conducted this week, has the main opposition Labour Party on 44 percent -- a whopping 25 points ahead of the Tories.

It also puts the Conservatives just four points ahead of Reform UK, a fringe right-wing party linked to Brexit cheerleader Nigel Farage which hits a new high of 15 percent.

The anti-immigrant upstarts are threatening to split the right-wing vote at the election, potentially depriving the Tories of several seats it needs to extend its 14 years in power.

YouGov found that less than half of voters who backed the Conservatives at the last election in 2019 when it won a landslide under Boris Johnson's leadership would back them again today.

The Conservatives are even losing support amongst their most traditional backers -- older voters, the polling firm said.

Tory support among that group sits at 32 percent while 26 percent intend to back Reform and 23 percent say they will vote Labour.

Sunak has failed to turn around his party's fortunes since succeeding Truss in October 2022 when she was forced out by Tory MPs after just 49 days in office.

British newspapers have reported in the past week that some disgruntled Conservatives are even plotting to replace Sunak before the nationwide vote, the date of which is yet to be announced.

The party has already served up five prime ministers since Britons voted to leave the European Union in 2016.

Labour, led by Keir Starmer, was last in government in 2010.