The UK's Brexit date of March 29 could be delayed if Labour forces a general election, Jeremy Corbyn has said.
In a high-profile speech, the Labour leader confirmed that his party will vote against Theresa May's Brexit deal next Tuesday and call a vote of no confidence in the Government if she loses, in the hope of forcing a general election.
He dismissed the Government's offer to consider new safeguards for workers as part of the Brexit package, backing a trade union assessment that "it simply doesn't guarantee the protections that we are seeking".
Mr Corbyn confirmed that Labour would go into any early election on a platform of opening new negotiations with Brussels on a Brexit deal involving a customs union, single market relationship and a guarantee to keep pace with EU rights and standards.
And he said that "time" would be needed to complete these talks.
Mr Corbyn said there was "no split" between him and shadow Brexit secretary Sir Keir Starmer, who suggested on Wednesday that an extension of the two-year period for negotiations set out in Article 50 of the EU treaties may now be "inevitable".
Asked if he agreed, the Labour leader said: "Quite clearly, moving into office at a period right up against the clock, there would need to be time for that negotiation.
"What Keir was doing was reflecting the practicalities of how that negotiation would be undertaken ... An extension would be a possibility because clearly there would have to be time to negotiate."
Speaking to party supporters in Wakefield, West Yorkshire, Mr Corbyn said a general election was the most "practical" and "democratic" way to "break the deadlock" in Parliament over Brexit
— Jeremy Corbyn (@jeremycorbyn) January 9, 2019
He said: "If the Government cannot pass its most important legislation, then there must be a general election at the earliest opportunity.
"A government that cannot get its business through the House of Commons is no government at all. It has lost its mandate so must go to the country to seek another."
And he added: "So I say to Theresa May: if you are so confident in your deal, call that election, and let the people decide.
"If not, Labour will table a motion of no confidence in the Government at the moment we judge it to have the best chance of success."
In a message apparently directed at Conservative rebels, Mr Corbyn urged MPs from across the Commons to join Labour in voting for an early poll to "break the deadlock".
"Clearly, Labour does not have enough MPs in parliament to win a confidence vote on its own," he said.
"So members across the House should vote with us to break the deadlock.
"This paralysis cannot continue. Uncertainty is putting people's jobs and livelihoods at risk."
The Labour leader said: "If a general election cannot be secured then we will keep all options on the table, including the option of campaigning for a public vote.
"But an election must be the priority. It is not only the most practical option, it is also the most democratic option.
"It could give the winning party a renewed mandate to negotiate a better deal for Britain and secure support for it in Parliament and across the country."
Defeat for Mrs May on her Government's central policy next Tuesday would be "historic" and would signal not only the failure of her premiership, but "the failure of the Conservative Party as a party of government", Mr Corbyn said.
He claimed that Labour's alternative Brexit deal was "practical and achievable, and clearly has the potential to command majority support in Parliament".
Promising to bring together Remain voters in inner-city seats like Tottenham and Leave backers in provincial towns like Mansfield, Mr Corbyn said the real divide in the country was between the many who "do the work, create the wealth and pay taxes" and the "few" who "set the rules, reap the rewards and so often dodge taxes".
He said: "People across the country, whether they voted Leave or Remain, know that the system isn't working for them.
"Some see the European Union as a defence against insecurity and hostility. Others see the European Union as part of an establishment that plunged them into insecurity and hostility in the first place.
"But it's the failed system rigged against the many to protect the interests of the few that is the real cause of inequality and insecurity, whether in Tottenham or Mansfield.
"And the real solution is to transform Britain to work in the interests of the vast majority, by challenging the entrenched power of a privileged elite. That is how we can help to overcome our country's divisions."