Labour has taken a 30-point opinion poll lead over the Tories - just days after Rishi Sunak said the UK was heading for a hung parliament.
YouGov put support for Keir Starmer’s party on 48%, with the Conservatives on just 18%.
Reform UK are just five points behind the Tories on 13%, with the Lib Dems on 9% and the Greens on 7%.
It is the biggest lead Labour has enjoyed since Liz Truss’s disastrous time as prime minister.
The poll is yet another hammer blow for Sunak, who is still reeling from Natalie Elphicke’s shock defection to Labour yesterday.
Earlier this week, the PM said last week’s local elections – in which the Tories lost nearly 500 council seats – “suggest we are heading for a hung parliament with Labour as the largest party”.
But according to the Electoral Calculus website, Labour would have a 452-seat majority if the YouGov poll was replicated at the general election, with the Tories left with just 13 seats.
Meanwhile, former chancellor Nadhim Zahawi has become the 64th Tory MP to announce that they are standing down at the next election.
Announcing his decision on X (formerly Twitter) he said: “The time is right for a new, energetic Conservative to fight for the honour of representing Stratford-on-Avon.”