What next? ... key dates in the countdown to deadline
With Prime Minister Theresa May facing a crucial week in the Brexit process as she seeks breakthroughs at home and abroad, we look at the key events of the days ahead.
This weekend: Talks were continuing last night between the Government and Labour on finding a way through the Brexit deadlock.
If no agreement is struck, but sufficient progress is made, it is possible dialogue could continue into the weekend.
Mrs May will use the next few days to spell out the UK's plans in a letter to European Council president Donald Tusk for the other 27 leaders to consider them before they gather in Brussels.
Monday April 8: The House of Lords considers the remaining stages of the European Union Withdrawal (No.5) Bill.
The Bill, brought forward by backbenchers including Labour's Yvette Cooper, allows Parliament to determine the length of any Brexit extension the Prime Minister should request at the EU summit on April 10.
If the Bill is passed by the Lords, it would go for Royal Assent. Any amendments to it would likely be considered by the Commons.
Tuesday April 9: If the Cooper Bill is passed, the Commons would vote on the length of any Brexit extension the Prime Minister should request at the EU summit.
If an agreement is reached between the Government and Labour, it could be debated and voted on by MPs.
The Government could also bring forward various Brexit options for MPs to vote on.
Wednesday April 10: Mrs May will be in the Commons for Prime Minister's Question Time.
She then travels to Brussels to address a meeting of the other 27 EU heads of government in the early evening.
To be granted a further postponement, the Government will have to set out what purpose it would achieve.
All 27 EU states would have to agree on any extension.
Thursday April 11: If the Cooper Bill has been passed by the Lords, it would place new requirements on the PM.
If the European Council proposes a different extension date, Mrs May would need to return to the Commons to obtain MPs' approval.
Final date for the UK to take steps to enable European Parliament elections to take place on May 23.
Friday April 12: If the Cooper Bill is passed, it would create the danger of an "accidental no-deal Brexit" on April 12, Downing Street warned.
If MPs said no to any new extension date proposed by the EU, there would be no time to renegotiate the date with Brussels.
The UK is scheduled to leave the EU on April 12 after MPs rejected the Prime Minister's deal.