Theresa May during Prime Minister's Questions in the House of Commons on Wednesday
MPs tonight will vote on whether or not to extend Article 50 and resultantly delay Britain leaving the European Union beyond the current March 29 deadline.
The government motion that will be put to the Commons states that if MPs back a Withdrawal Agreement by March 20, the Prime Minister will seek a one-off extension to June 30 to pass necessary legislation.
However, the motion also notes that if the Commons has not passed a resolution approving the negotiated Withdrawal Agreement by March 20, then it is "highly likely" the European Council would require a "clear purpose for any extension" and to determine its length.
Any extension beyond June 30th would require UK to hold European elections in May.
How long would the extension to Article 50 be?
The current proposal to be voted upon would delay Brexit until June 30, however many MPs and European leaders have suggested any extension should be much longer.
Speaker of the House John Bercow said on Wednesday that the government motion will be amendable, meaning MPs may try to gain a majority for the length of the delay or type of Brexit as part of the extension.
Some MPs have already proposed extending Article 50 until the end of this year, while it has been reported the EU could even seek a delay to Brexit until 2021.
This would see the planned 21-month Brexit transition period replaced by a longer postponement to the UK’s departure.
Following the rejection of no deal on Wednesday Theresa May said "a short technical extension is only likely to be on offer if we have a deal in place.
"Therefore the House has to understand and accept that if it is not able to support a deal in the coming days and if it is not willing to support leaving without a deal on the 29th of March then it is suggesting that there will need to be a much longer extension to Article 50.
"I do not think that would be the right outcome. But the House needs to face up to the consequences of the decisions it has taken."
Will the EU agree to extend article 50?
If the motion is passed, Theresa May will formally ask European leaders for the Article 50 process to be extended.
The EU27 must then unanimously agree to her request.
EU leaders are likely to agree to an extension as long as there is a clear prospect of a deal being reached – or a referendum or general election which could significantly change the British political landscape.
German Chancellor Angela Merkel on Wednesday refused to say how long she thinks a possible delay to Brexit should be, but said it was in "our mutual interest that we achieve an orderly departure".
French president Emmanuel Macron said Britain needed a clear reason for requesting an extension and extra time could not be used to renegotiate the withdrawal.
The EU’s chief Brexit negotiator Michel Barnier said London must decide what it wants from Brexit before Brussels will consider a delay.
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What are the consequences of extending Article?
Article 50 is the legal mechanism within the Treaty on European Union, commonly known as the Lisbon Treaty, by which a member state can quit the bloc.
By invoking Article 50 on 2 October 2016 the UK triggered its withdrawal from the EU, giving it two years to negotiate an exit deal.
Seeking an extension to Article 50 simply prolongs that negotiation period, pushing back the final date on which the UK will officially leave the EU.
Only by revoking Article 50 would Brexit be cancelled.