Reform UK is on course to unseat five Cabinet ministers at the next election, as well as ousting Angela Rayner.
Internal polling for Reform, seen by The Telegraph, shows the party on course to take 110 seats from Labour at the next election.
Labour suffered an historic defeat in the local elections on May 8, losing 1,496 council seats across England and giving up power in the Welsh Senedd for the first time since devolution. It also lost former stronghold councils in the Red Wall of the North to a Reform surge.
Reform’s polling shows five serving Cabinet ministers at risk of losing their seats to Reform at the next general election in 2029.
Yvette Cooper, the Foreign Secretary, would be ousted in Pontefract, Castleford and Knottingley, a seat she holds with a 17,089 majority, while Bridget Phillipson, the Education Secretary, would lose her seat of Houghton and Sunderland South, which she has held since 2010.
Pat McFadden, the Work and Pensions Secretary, would be ousted in Wolverhampton South East, a seat he has held since 2005.
Jonathan Reynolds, the Chief Whip, would be ousted in Stalybridge and Hyde, and Lisa Nandy, the Culture Secretary, would also lose her seat in Wigan, which she has held since 2010.
Reform took control of Tameside council last week, which encompasses Ashton-under-Lyne, the constituency of Ms Rayner, the former deputy prime minister. That too is set to fall to Reform in 2029.
The polling is based on the votes cast in the local elections, and confirms the recent findings of seat-level polling from Electoral Calculus.
It suggests that if the swings in each council last week were applied to the general election results, Reform would seize 110 seats currently held by Labour, while the Greens would take 24 seats from Labour.
The analysis suggests that Nigel Farage’s party poses a significantly greater threat to Labour’s hopes of re-election than the Greens.
Voters often behave differently when electing local councillors and returning MPs to Westminster, meaning last Thursday’s swing is unlikely to be replicated in a general election.
But all recent large projections adjusting for demographics and past voting behaviour conducted by Electoral Calculus, More in Common and YouGov alike, suggest a Labour wipeout, and Reform emerging as the largest party were a national ballot to be held.
Cabinet seats at risk to Zack Polanski’s Green Party in the polling conducted for Reform were those of David Lammy, the Justice Secretary, Hilary Benn, the Northern Ireland Secretary, and Lucy Powell, the deputy Labour leader.
Sir Keir Starmer is under pressure from some of his backbenchers and potential leadership rivals to tack further to the Left as the price of remaining at No 10.
The Prime Minister has been urged to consider a wealth tax, or loosening of the fiscal rules to allow more borrowing and public spending.
But while the Greens pose a threat on Labour’s Left flank, the party is more at risk of losing voters to the Right, as Morgan McSweeney, No 10’s former chief of staff, has warned.
As well as haemorrhaging votes to Mr Farage’s movement, which could take 110 seats, Labour is also vulnerable to the Tories, the polling suggests.
It predicts that Labour would lose 22 seats to the Conservatives, mostly in outer London where Kemi Badenoch’s party did well at the local elections.
Reform’s analysis found that a further 10 Labour seats would fall to the Liberal Democrats, taking its total losses to 168 – two-fifths of all the constituencies it currently holds.