Jeremy Corbyn has promised to put wealth "in the hands of the people of Britain" as he turned his fire on big business and the rich in his first major speech of the general election campaign.
The Labour leader cast the June 8 poll as a battle of "the Establishment versus the people", as he promised to overturn a "rigged system" which allowed the rich and powerful to extract wealth from the nation.
A "morally bankrupt" Conservative Party was intent on preserving the system while cutting public services and blaming migrants and the unemployed for the woes of the economy, he said.
And he told an audience of activists in central London: "It is the rigged economy the Tories are protecting that Labour is committed to challenging.
"We will not let the elite extract wealth from the pockets of ordinary working people any longer."
Controversial business figures like Mike Ashley of Sports Direct, Sir Philip Green, Southern Rail and tax-avoiding multinationals should be "worried" about the prospect of a Labour government, said Mr Corbyn.
"Those are the people who are monopolising the wealth that should be shared by each and every one of us in this country," he said.
"It is wealth that should belong to the majority and not a tiny minority."
He vowed: "We will no longer allow those at the top to leech off of those who bust their guts on zero hours contracts or those forced to make sacrifices to pay their mortgage or their rent.
"Instead of the country's wealth being hidden in tax havens, we will put it in the hands of the people of Britain, as they are the ones who earned it."
Mr Corbyn's speech came amid speculation about Labour's taxation plans, after shadow chancellor John McDonnell suggested the wealthy, who he defined as earning over £70,000 a year, should ''pay their way more''.
But shadow foreign secretary Emily Thornberry played down suggestions new taxes might be introduced at this level, telling BBC Radio 4's Today programme she understood why "many people" on this salary might feel they are "not rich".
Labour is "prepared to make radical change" and stand up to the elites, but this did not mean "picking off people of particular incomes", she said.
Mr Corbyn promised he would not "play by the rules" if he won the election, but would take on the "cosy cartels that are hoarding this country's wealth for themselves".
Despite polls putting Labour as many as 21 points behind the Tories, he insisted the election result was not a "foregone conclusion", declaring: "Things can, and they will, change."
While Mrs May sought to frame the election as about Brexit, he insisted it was a battle of "the Conservatives, the party of privilege and the richest, versus the Labour Party, the party that is standing up for working people to improve the lives of all".
Under his leadership, Labour was not part of the "cosy club" at Westminster which thinks it is natural for Britain to be "governed by a ruling elite, the City and the tax-dodgers", he said.
"We don't accept that the British people just have to take what they're given, that they don't deserve better," said Mr Corbyn.
"In a sense, the Establishment and their followers in the media are quite right. I don't play by their rules.
"And if a Labour Government is elected on 8 June, then we won't play by their rules either.
"They are yesterday's rules, set by failed political and corporate elites we should be consigning to the past.
"It is these rules that have allowed a cosy cartel to rig the system in favour of a few powerful and wealthy individuals and corporations.
"It is a rigged system set up by the wealth extractors, for the wealth extractors.
"But things can, and they will, change."