Keir Starmer has branded the government’s tax cuts for the rich as a “piss take”.
The Labour leader turned the air blue at a reception at the start of the party’s annual conference in Liverpool on Saturday night.
Chancellor Kwasi Kwarteng announced on Friday that he was abolishing the 45p income tax rate currently paid by anyone earning more than £150,000 a year.
It means that around 660,000 of the richest people in the country will save an average of £10,000 on their income tax bill.
Kwarteng also scrapped the rise in national insurance contributions, cancelled a planned rise in corporation tax and ended the cap on bankers’ bonuses.
Speaking at a conference reception, Starmer said: “That’s their politics - make the rich richer, make the super rich even richer.
″And the theory is that if they’re made even richer, some of it may one day trickle down into the pockets of other people.
“It didn’t work last time. Trickle down - it’s a piss take.”
Labour will this week set out how it plans to spend £28 billion boosting green projects to grow the economy and bring down energy bills.
According to The Observer, Starmer will pledge to double the amount of onshore wind, triple solar and more than quadruple offshore wind power by 2030.