A left-wing MP was branded an “idiotic embarrassment” after demanding a new wealth tax.
Richard Burgon, who currently sits as an independent after having the Labour whip suspended, was one of 30 MPs who signed a letter calling for a 2% levy on assets over £10 million.
But former Conservative chairman Richard Holden warned the move would cost the Treasury as it would drive out the super-rich.
Mr Holden, who represents Basildon and Billericay wrote on X: “What an idiotic embarrassment this man and his fellow travellers from Labour are.
“Why would any person or business hold UK assets if they’re taxed for holding them when they’re not elsewhere, therefore it wouldn’t just jot raise money, it’d cost the exchequer, and therefore other taxpayers, a fortune.
“These are the morons that prop up Sir Keir Starmer and his lazy Government.”
Mr Burgon, who had the Labour whip suspended after rebelling over the two-child benefit cap, shared a picture of the letter which was also signed by former Labour leader Jeremy Corbyn.
He said: “Those with extreme wealth should be the ones made to pay for fixing the mess the Tories left behind.
“A wealth tax of 2% on assets over £10 million would raise £24 billion per year.
“I’ve signed this letter, backed by dozens of MPs, calling for the Government to do this.”
Other signatories include ex-shadow chancellor John McDonnell and former shadow home secretary Diane Abbott.
It comes as Chancellor Rachel Reeves is expected to make up to £40 billion of tax hikes in the Budget on October 30.