Rishi Sunak’s own pollster has quit No.10 having concluded the country is on course for a “decade of Labour rule”.
Will Dry said the Conservative Party was “heading for the most almighty of defeats” at the general election.
In a statement to The Sun, he also warned that if Nigel Farage returned to frontline politics with Reform UK then the Tories “essentially won’t exist by Christmas”.
Dry is reported to have helped draw up the questions for the recent huge YouGov poll of 14,000 people on behalf of the Conservative Britain Alliance group that suggested the Tories were heading for a 1997-style wipeout.
It comes after former cabinet minister Simon Clarke called for Sunak to be ousted as Tory leader as the party was set to be “massacred” at the ballot box.
His intervention was met with a fierce backlash from other Tory MPs, including former home secretary Priti Patel who slammed it as “facile and divisive self indulgence”.
In an interview with the BBC, Clarke said he was acting “on my own” and was not part of an organised move to get rid of the prime minister.
But according to The Times, a rebel group of around ten Tory MPs are working together from a base in central London in the hope of installing a new party leader ahead of the election.
In his statement on Wednesday evening, Dry - who was a prominent pro-Remain campaigner before and after the Brexit referendum - said: “I resigned before Christmas after steadily becoming more dispirited.
“Everyone in this country can see just how colossal the challenges we face are. Sadly, it became clear to me we weren’t providing the bold, decisive action required to overcome those challenges.
“You cannot dent them without internalising just how fundamentally broken our political system is.
“I further concluded, again sorrowfully, that the Conservatives are heading for the most almighty of defeats.
“Be in no doubt: we are on course for at least a decade of Labour rule. And if Farage comes back, the Conservative Party essentially won’t exist by Christmas.”
Earlier this month, the right-wing Reform UK party said Farage was still “assessing” whether to take a leading role in its election campaign.
Meanwhile a new poll by YouGov for the Fabian Society, showed Keir Starmer’s Labour is 34 points ahead of the Conservatives in their 150 target sears.