With fears that there is now insufficient time for a legal text to be hammered out in time, a compromise could see EU leaders back a political agreement and a second summit scheduled. 

But will the Benn Act come into play as part of the Brexit negotiations? Here's everything you need to know about the Benn Act. 

What is the Benn Act? 

The Benn Act is actually the EU Withdrawal (No.2 Act) and requires Boris Johnson to get MPs to vote for a new Brexit deal or agree to a no-deal exit by 19 October or if he fails to do so, ask the EU for an extension to article 50 until 31 January 2020.

READ MORE: Ruth Davidson and Tony Blair in secret talks about indyref2 

How did it pass? 

The Act was passed after an emergency debate motion on 3 September took control of the order paper the following day. It included provisions which allowed the bill to go through all Commons stages on 4 September with the bill being suggested by Hilary Benn. 

The Bill passed on the 5th, going through the Lords of the 6th and receiving Royal Assent on September 9. 

The bill passed its third reading by 327 votes to 299

Is it different to the Surrender Act?

No. The Benn Act has been dubbed the Surrender Act by Boris Johnson, but it has been dubbed the latter name by Boris Johnson and those opposed to a Brexit extension. 

What does the Bill say?

If MPs haven’t approved a deal in a meaningful vote, or approved leaving the EU without a deal by 19 October, then the prime minister must send a letter to the president of the European Council which seeks an extension to Article 50 until 31 January 2020. If the EU agrees to the date, then the prime minister should also agree.

If the EU proposes an alternative date, then the prime minister should agree to it, unless MPs do not vote for a motion – within two days – which approves the date suggested by the EU.

READ MORE: Nicola Sturgeon: New Brexit deal treats Scotland unfairly 

If an extension is agreed, then the Act requires the secretary of state for exiting the EU to publish a report on progress made on negotiations by 30 November 2019.  This would create a five-day window for MPs to vote on the act. 

The Act requires the secretary of state to publish further reports every 28 calendar days from 7 February 2020 until the UK reaches a deal with the EU – or the House of Commons decides it doesn’t need to.

READ MORE: Government 'may challenge Benn Act' to rule out Brexit extension 

The Act amends the EU Withdrawal Act 2018 to say that ministers “must” amend the date of exit by statutory instrument, rather than “may” amend the date of exit.

Could it impact Brexit negotiations?

If no deal is struck on Thursday, then talks between the European leaders could continue into Friday.

Under the terms of the Benn Act, Mr Johnson would have to delay Brexit beyond October 31 unless a deal is agreed which could then be put to MPs on Saturday.

MPs could also look to bolster the Benn Act if the deal is not voted through, or potentially seek further resolution through a People's Vote.