Labour's leadership battle lurched to the Left again today as Wes Streeting called for a wealth tax.
The former health secretary - seen as the Blairite candidate - called for a levy on the 'rich' that could bring in £12billion a year.
The intervention comes as nervous markets brace for a 'bidding war' in Labour that could drive the party towards more extreme policies.
Big beasts are gearing up for a contest to replace Keir Starmer within months, whether or not Andy Burnham wins the Makerfield by-election on June 18.
Rachel Reeves has already pushed the tax burden towards a record high, squeezing growth and investment.
And there are fears a new spending bonanza could send the costs of servicing the UK debt mountain spiralling.
Wes Streeting - seen as the Blairite candidate - called for a levy on the 'rich' that could bring in £12billion a year
Mr Streeting laid out his plans for tax increases in an interview with the BBC's Political Thinking podcast.
He said: 'A member of my family is a cleaner in Lancashire. She pays a higher tax rate on her salary than her landlord pays for the growing value of the home she lives in.
'She slogs her guts out, he puts in far less effort, yet the state rewards him more than her.
'And we wonder why people are angry.
'The system is penalising work. It's not fair and it's bad for our economy. We need a wealth tax that works.
'A pound made from simply owning assets should not be taxed less than a pound made from a hard day's work.'
He added: 'The wealth gap in this country has widened... and the gap between earned income and unearned income has widened.'
Higher or additional rate taxpayers pay 24 per cent on gains they make in the current financial year.
Under Mr Streeting's proposal that would be equalised with the income tax rate of 40 per cent for higher rate taxpayers and 45 per cent for additional rate taxpayers.
He vowed to do it alongside measures to protect real entrepreneurs – with lower capital gains tax rates for those taking risks building companies – and long-term investment to boost economic growth.
The package would also close the loopholes he said people use to disguise income from work as capital gains, such as establishing personal service companies or taking pay in shares.
He claimed the plan could raise up to £12billion a year, pointing to calculations by the Centre for the Analysis of Taxation.
But the boss of one London hedge fund told the Daily Mail: 'I was optimistic Wes Streeting might be OK but he's clearly an idiot, too.
'How do you sell a business if the stock market is broken?'
'Why can't these clowns understand that if you keep driving out the wealth creators there will be no one left to fund their mad socialist policies?'
The MP's intervention comes a day after he warned in his resignation speech that Labour must change course or risk handing Reform UK power, and after he quit the Cabinet last week calling on the Prime Minister to go.