Both Betfair and Paddy Power have shorter odds on the Labour leader becoming prime minister than any Conservative candidate.
Mr Corbyn is 6/1 to succeed Theresa May at No 10 – ahead of leading Tory figures including Boris Johnson on 13/2, Michael Gove on 7/1 and Jeremy Hunt at 11/1, according to Oddschecker, which compiles odds from all the leading bookies.
It follows a tumultuous 48 hours at Westminster, with Ms May’s Wednesday night Brexit speech attacking parliament causing intense anger among MPs.
Sir Graham Brady, the chairman of her party’s influential 1922 committee, has reportedly told Ms May that many Tory MPs want her to quit after he was “bombarded with text messages”.
The prime minister is facing a third Commons defeat on her deal next week, and a rift has reportedly opened up between No10 and Chief Whip Julian Smith’s office over her handling of Brexit.
With the government in turmoil, the odds of general election taking place this year have been slashed, with Ladbrokes putting the chances at 5/4. The month of May – at 5/2 – is deemed the most likely time it could take place.
Jessica Bridge of Ladbrokes said: “If the odds are to be believed, May’s speech doesn’t seem to have done the trick.”
The odds of Ms May being replaced at No.10 this year have been cut by Ladbrokes to 1/6. “As far as the odds are concerned things are going from bad to worse for the prime minister,” Ms Bridge added.
Betfair has the Labour leader as 4/1 favourite to be the next prime minister, compared with 6/1 odds for Mr Johnson, while William Hill has Mr Gove as 4/1 favourite ahead of Mr Corbyn and Mr Johnson on 5/1.
Although Ms May won a Conservative party no-confidence vote in December, preventing her opponents from bringing the formal process again until the end of 2019, Tory MPs could put pressure on her to resign.
Another route to Ms May’s exit comes from the opposition. The Labour leader has threatened to call a fresh confidence vote in the government if Ms May’s deal fails to pass the Commons a third time – although such a move is unlikely to win backing from Tory MPs.
“At that point the confidence motion would be appropriate,” Mr Corbyn told Sky News’ Sophy Ridge on Sunday ahead of another meaningful vote. “I think at that point we should say there has to be a general election.”
Editor of The Spectator Fraser Nelson has suggested an offer by Ms May to stand down soon might be enough to get her deal through, describing resignation as “her most powerful card”.
Goldman Sachs analysts have increased their estimated likelihood of the UK crashing out of the EU without a deal to 15 per cent from 5 per cent.