Theresa May’s Brexit plan has been defeated for a third time in parliament despite a large number of Tory rebels finally backing it.

The House of Commons voted against the deal by 344 votes to 286 - a majority of 58 - after the government scheduled a last-minute vote on the day Britain was supposed to be leaving the EU.

While the defeat marked a major reduction in MPs' opposition to the plan, which was rejected by 149 votes earlier this month, it will still come as a major blow to the prime minister as she struggles to find a way to deliver Brexit.

Ms May had asked MPs to vote only on the legally-binding withdrawal agreement part of her deal, rather than putting both that and the non-binding political declaration on the future UK-EU relationship in front of the Commons, as she had in the previous two votes.

The move was a last-ditch attempt to have the deal approved in time to meet a deadline set by the European Council, which said the withdrawal agreement must be passed this week if the UK is to leave the bloc with a deal on 22 May.

But while the government won over dozens of Conservatives MPs who had previously voted against its plan, it was not enough to stop the deal behind comprehensively rejected.

The UK will now have to put forward an alternative plan to the EU or face leaving the bloc without a deal on 12 April.

Speaking immediately after the vote, Ms May told MPs it was likely that the UK would now have to seek a long delay to Brexit and hold European Parliament elections in May.

She said: "The implications of the House’s decision are grave.

"The legal default now is that the United Kingdom is due to leave the European Union on 12 April - in just 14 days’ time.

"This is not enough time to agree, legislate for and ratify a deal, and yet the House has been clear it will not permit leaving without a deal, and so we will have to agree an alternative way forward."

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She continued: "The European Union has been clear that any further extension will need to have a clear purpose and will need to be agreed unanimously by the heads of the other 27 member states ahead of 12 April.

"It is also almost certain to involve the UK being required to hold European Parliamentary elections."

In a move likely to fuel speculation that she may be considering calling a general election, Ms May added: "I fear we are reaching the limits of this process in this House.

"This House has rejected no deal, it has rejected no Brexit. On Wednesday it rejected all the variations of the deal on the table. And today it has rejected approving the withdrawal agreement alone and continuing a process on the future."

Theresa May: 'This is the last opportunity to guarantee Brexit'

The EU immediately responded to the latest defeat by calling an emergency European Council summit for 10 April - two days before the UK is currently due to leave the bloc.

Opposition parties said Ms May must now accept that her deal was dead.

Labour leader Jeremy Corbyn said: “This is now the third time that the prime minister’s deal has been rejected.

“When it was defeated the first time the prime minister, said 'It is clear that this House does not support the deal.'