MPs have returned to Westminster after the prorogation of Parliament was ruled unlawful by the Supreme Court.
Following the bombshell judgment, the PA news agency takes a look at key dates in the coming weeks which could shape when, how and if Britain leaves the European Union this year.
– September 25
MPs took their seats on the green benches in the Commons at 11.30am on Wednesday after Speaker John Bercow announced Parliament would resume the day after the Supreme Court ruling.
Parliament had been suspended, but it resumed without a state opening as the court’s president Lady Hale said it had never actually been prorogued.
– September 29
The Conservative Party’s annual conference is set to kick off in Manchester – but it remains unclear how many MPs will be able to attend the gathering.
Parliament usually enters a conference recess to allow parliamentarians to attend the party gatherings, but with the Commons back in business, they may not be able to go.
The Government could table a motion for a short recess, but will need the backing of opposition MPs who are now even less likely to be sympathetic to the Conservatives.
– September 30
Finnish prime minister Antti Rinne put pressure on the PM to formally outline his plans to the EU by the end of September.
But the Government has said Boris Johnson will not be bound by an “artificial deadline” to produce formal written proposals.
– October 14
The Queen was due to formally open Parliament on this day, following the prorogation, and her speech would set out the Government’s new legislative agenda.
It could still happen on this date if Parliament is prorogued again in the meantime, or it may be brought forward or pushed back.
However, with the Queen still at Balmoral and not expected to return until early next month, it seems unlikely a state opening of Parliament will take place before then.
– October 16-17
The Prime Minister will head to Brussels for what is supposed to be the UK’s last European Council summit.
He says he is hoping to secure a new or amended deal with the EU at the Brussels gathering, so he can deliver Brexit later in the month with a deal.
But formal proposals for how to change the deal offered to Theresa May have yet to be submitted.
– October 19
Under the so-called Benn Act, which seeks to prevent a no-deal Brexit, the Government will be forced to seek a delay beyond October 31 unless a divorce deal is approved or Parliament agrees to leaving the EU without one by October 19.
If no agreement is met, the PM would have to send a letter to the president of the European Council requesting an extension to Article 50 until January 31.
– October 31
The date on which Britain is scheduled to leave the European Union – with or without a deal – unless an extension is agreed by the EU.
Mr Johnson has repeatedly insisted he will not countenance a delay beyond this date, saying he would rather be “dead in a ditch” than extend Britain’s membership of the EU.
– November or December
The Government has twice asked MPs to support a general election, but opposition parties have voted against the move because they are concerned a no-deal Brexit could take place during the campaign, when Parliament would not be sitting.
MPs have instead said they will support an election once the Government has secured an extension to Britain’s EU membership – which could lead to an election some time in November or December.