Pressed on whether he would forge an alliance with the SNP and the Lib Dems to win the keys to Downing Street, the Labour leader said: ‘You’d better ask me that on June 9.’
The comments will fuel fears that failure by Theresa May to secure outright victory next week could open the door to a ‘coalition of chaos’.
Mr Corbyn has already said that in No10 he would ‘open discussions’ with Miss Sturgeon about her demand for a fresh independence referendum.
Meanwhile, the veteran left-winger has tried to wrongfoot Mrs May by declaring he will take part in a TV General Election debate tonight.
Both the main party leaders had been expected to boycott the event and send deputies – but Mr Corbyn has gambled by deciding he will go along.
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Jeremy Corbyn, pictured at a campaign event in Westminster this morning, will appear in the televised leaders head to head tonight
Mrs Sturgeon, pictured on the campaign trail in Anstruther today, has been demanding a fresh Scottish independence referendum as soon as the terms of any Brexit deal are clear
The PM was out inspecting samples of cheese in Shepton Mallet today. Bookies have shortened the odds on her taking part in tonight’s televised General Election debate after Corbyn’s decision, but she is still odds-on to stay away
Mrs May dismissed accusations that she is running scared this afternoon, insisting she would be out talking to voters while the other politicians were ‘squabbling’.
Home Secretary Amber Rudd will represent the Conservatives. Lib Dem leader Tim Farron, Caroline Lucas for the Greens, Leanne Wood for Plaid Cymru, and the SNP’s leader at Westminster Angus Robertson will also share the stage.
Announcing his decision, Mr Corbyn said: ‘I will be taking part in tonight’s debate because I believe we must give people the chance to hear and engage with the leaders of the main parties before they vote.
‘I have never been afraid of a debate in my life. Labour’s campaign has been about taking our polices to people across the country and listening to the concerns of voters.
‘The Tories have been conducting a stage-managed arms-length campaign and have treated the public with contempt.
‘Refusing to join me in Cambridge tonight would be another sign of Theresa May’s weakness, not strength.’
The Prime Minister refused to take part in head-to-head debates with any other party leaders during the campaign for the June 8 election.
The Labour leader and the PM both appeared on a Channel 4 / Sky debate last Friday – but they were interviewed separately and never appeared on stage together.
Mr Corbyn’s decision comes after he used a campaign even in central London to challenge the PM to debate him head to head on TV.
The Labour leader said it was ‘ridiculous’ that the PM is refusing to debate him directly on the same stage.
He said: ‘How ridiculous is that?
Theresa May, pictured out on the campaign trail today in Somerset, has refused to take part in nay live head to head with other party leaders
The Tories have raised fears that Mr Corbyn could make significant concessions to Nicola Sturgeon (pictured campaigning in Anstruther today) to become PM if there is a hung parliament
‘Come on, Prime Minister, come and have a chat, come and have a debate. I can be ever so polite, but there are a number of questions I want to put to you.’
His decision piles pressure on the PM to follow suit and appear on the show.
Bookmakers Ladbrokes have shortened the odds of Mrs May taking part from 10/1 to 3/1, although she is still odds-on to stick with her boycott.
But out campaigning in Bath today, Mrs May said: ‘I think debates where the politicians are squabbling among themselves doesn’t do anything for the process of electioneering.
FALKLANDS VETERANS VOICE ‘HORROR’ AT IDEA OF PM CORBYN
Falklands veterans have voiced ‘horror’ at the prospect of Jeremy Corbyn becoming PM after he said reclaiming the islands from Argentina by force was wrong.
Major-General Julian Thompson, who led British forces to victory in 1982, raised fears that the Labour leader could do ‘some deal’ with Buenos Aires over the territory.
Simon Weston, the Welsh Guardsman who suffered terrible burns when his ship was bombed by Argentine jets, branded Mr Corbyn’s stance ‘crassly stupid’.
In a TV election programme earlier this week, the veteran left-winger accused Margaret Thatcher of making a ‘great deal’ of Argentina’s invasion.
Pressed on his previous description of the war as a ‘Tory plot’ and ‘flag-waving nonsense’, Mr Corbyn made clear he believed it should have been resolved through the UN – even though that was regarded as diplomatically impossible.
‘What I wanted was a stopping of that war.’
Asked whether he thought the UK should not have protected the Falklands, the Labour leader said: ‘I don’t think they should have gone in there but I also think there should have been an opportunity to stop that war happening.’
‘I think it’s about getting out and about, meeting voters and hearing directly from voters.’
She insisted she had been taking on Mr Corbyn ‘week in week out’ at PMQs.
‘Public scrutiny is for an election campaign. That’s why taking questions from members of the public who are going to be voting on 8 June is so important,’ the PM said.
‘That’s what I enjoy doing during the campaigns. And I think that’s really important. That is why I’ve been doing that up and down the country.
In an interview with ITV this afternoon, Mr Corbyn was repeatedly challenged on how he would respond if there was a hung parliament.
Initially he insisted Labour was ‘fighting to win this election’.
But asked for a third time Mr Corbyn said: ‘Well, you’d better ask me that on June 9.’
Mr Corbyn has cancelled planned appearances at stump events in Swindon and Stroud tonight, and a rally in Bristol.
The events will go ahead with shadow education secretary Angela Rayner and shadow health secretary Jon Ashworth filling in, a Labour source said.
The PM and Mr Corbyn both boycotted the first televised leaders election debate of the campaign, held on ITV earlier this month.
The show was widely mocked and branded a borefest by viewers, who pointed out that no one taking part stood a chance of leading a government after June 8.
It was most notable for Ukip leader Paul Nuttall repeatedly calling Plaid leader Leanne Wood ‘Natalie’.
Conservative Party Chairman Patrick McLoughlin said: ‘Jeremy Corbyn has made clear that he will do a deal in order to get the keys to Downing Street.
‘Corbyn propped up by the Lib Dems and the SNP in a coalition of chaos would be a disaster for Britain and would mean a bad Brexit deal, higher taxes, more borrowing and weaker defences.
‘If you don’t think Jeremy Corbyn is fit to be Prime Minister, if you don’t think he’s up to negotiating Brexit, if you oppose a second referendum – vote for Theresa May and her Conservative team.’
Just five leaders went head to head in the ITV televised debate earlier this month. The show was mocked and branded a borefest by viewers who were quick to point out that none of the leaders involved in it stood any chance of leading a government after June 8