Jeremy Corbyn vowed to “transform” Britain by taking on “the few who run a corrupt system” as he kicked off Labour’s election campaign.
The party leader promised to “rebuild” public services and hit out at “tax dodgers, dodgy landlords, bad bosses and big polluters”.
In a speech, Mr Corbyn called the 12 December poll a “once-in-a-generation chance to transform our country”.
But Prime Minister Boris Johnson blamed Mr Corbyn for the delay to Brexit.
Both leaders, and those of other parties, are beginning six weeks of campaigning ahead of the election.
In a speech in Battersea, south London, Mr Corbyn received loud cheers from supporters when he said Labour would launch “the biggest people-powered campaign in history”.
Flanked by members of the shadow cabinet, he said: “You know what really scares the elite? What they’re actually afraid of is paying their taxes. So in this election they’ll fight harder and dirtier than ever before. They’ll throw everything at us because they know we’re not afraid to take them on.
“So we’re going after the tax dodgers. We’re going after the dodgy landlords. We’re going after the bad bosses. We’re going after the big polluters. Because we know whose side we’re on.”
The December election, called for by the prime minister, is taking place after Mr Corbyn agreed to it following the EU delaying Brexit.
The Labour leader told the audience that, if he got to Downing Street, he would “open negotiations with the EU about a sensible relationship with Europe”.
This wasn’t exactly a pitch for the centre ground by Jeremy Corbyn.
His tone was uncompromising.
It’s designed in part – just like in 2017 – to enthuse younger voters and previous non-voters, convincing them that politics can make a difference.
But he is also searching for a message that might appeal beyond Brexit – to potential Labour voters in both Leave and Remain areas.
Labour launched its election campaign in the London seat of Battersea.
It doggedly campaigned here in 2017, and won narrowly – it now leads the Conservatives by just 2,416 votes.
It’s a reminder that the party will have to work hard to defend seats – as well as targets held by its opponents.
Mr Corbyn also said: “The prime minister wants you to believe that we’re having this election because Brexit is being blocked by an establishment elite.
“People aren’t fooled so easily. They know the Conservatives are the establishment elite.”
Mr Corbyn also said the NHS was “not for sale” and that any future trade deal with the US should not involve giving companies from that country greater access to it.
After this, the audience, made up of Labour supporters, repeatedly chanted: “Not for sale.”
Several times he asked the audience: “Whose side are you on?” They replied: “Yours.”
Mr Corbyn said the prime minister had thought he was being “smart” in calling for an election in December, and thought that Labour supporters “won’t go out to vote”.
He added: “Even if the rivers freeze over, we’re going out to bring about real change for the many, not the few.”
But the Conservatives’ campaign chairman James Cleverly said voting for Labour was “precisely the opposite” to a “vote for change”.
He said Labour would offer “more delay and uncertainty on Brexit, meaning the government can’t focus on people’s priorities, like the NHS, schools and crime”.
Marking 100 days as prime minister in a campaign speech on Thursday – the day Brexit had been scheduled to take place – Boris Johnson will say: “Despite the great new deal I agreed with the EU, Jeremy Corbyn refused to allow that to happen – insisting upon more dither, more delay and more uncertainty for families and business.”
Transport Secretary Grant Shapps also laid blame with MPs, telling BBC Radio 4’s Today programme: “It is quite clearly Parliament that has failed to deliver it. [Mr Johnson] did absolutely everything in his power to get Parliament to come its senses.”
Meanwhile, Liberal Democrat leader Jo Swinson has defended her decision to campaign as a “candidate to be prime minister”, denying such an outcome was a fantasy.
She told the BBC’s Andrew Neil the UK was in a “very volatile political situation” and anything could happen on 12 December.
“We have seen many unprecedented political results in recent years,” she said.
As other smaller parties geared up for their election campaigns, the Daily Telegraph reported that the Brexit Party was considering helping the Tories to secure a majority by withdrawing hundreds of its general election candidates.
Brexit Party sources told PA news agency the report was “wild speculation”.
What happens next?
- Having been approved by the Lords, the early election bill will receive Royal Assent – when the Queen formally agrees to the bill becoming law
- On Monday 4 November, MPs are due to elect a new speaker to replace John Bercow
- Just after midnight on Wednesday, 6 November, Parliament will be shut down or be “dissolved” – meaning every seat in the House of Commons becomes vacant
- The electoral authorities have set a deadline of the end of Tuesday 26 November for people to register to vote.
- The cut-off point to apply for postal votes is the same day, but at 17:00 GMT.