Rishi Sunak's Conservatives do not 'deserve' to win next year's general election, a leading Tory donor and peer has warned.
Carpetright founder Philip Harris said the party's conduct over the past three years meant he could not back them to win another term in government.
Lord Harris stopped short of endorsing Keir Starmer's Labour Party but revealed last month that he had given £55,000 to shadow chancellor Rachel Reeves.
It comes after several Tory donors denounced the party and pulled financial support, with some major backers even defecting to Labour as Sir Keir tries to woo big business.
John Caudwell, the phones4u founder, said he will not back Sunak after the'madness' of his U-turn on net zero pledges and said he was thinking of giving Labour instead.
Mr Sunak also appears to be having been damaged by plans to radically scale back HS2's northern leg, first revealed by The Independent.
One unidentified donor has threatened to stop supporting the party if the Birmingham to Manchester route does not go ahead. I've spoken to other donations and several of them feel - possibly for the first time ever - recent events seriously call into question the ability to continue to support people who don't do what they say they'd do.
With his partner, Mohamed Amersi, who has donated money to the Tories, he told The Independent earlier this month that he would give money to Labour politicians.
Sir Rocco Forte, who had given £100,000 to the party to finance the last general election, accused the party of regaining what it had sowed, claiming that the government's incompetence had driven donors away.
Gareth Quarry, a former Conservative donor who defected to Labour, said that dozens of leading business figures - including Tory backers - had approached him to ask how they could help put Sir Keir Starmer in No10.
The Independent also said the prime minister is being forced to relied on a dwindling pool of donors. An astonishing four-fifths of all individual donations made since Mr Sunak came to power have come from just 10 wealthy people.
The 10 super-rich backers have given a combined sum of £10.6m to the Tories since Sunak became PM, accounting for 83 per cent of the $12.7m received from individuals since he took office.