Boris Johnson's Brexit plans could face three critical tests in the space of a week next month after a judge agreed to fast-track a case brought by pro-Remain campaigners.
The group - including more than 70 MPs and peers of various parties - have filed a petition at the Court of Session in Edinburgh.
They are bidding to stop the prime minister from being able to temporarily suspend parliament in order to push through a no-deal Brexit.
On Tuesday, Judge Lord Raymond Doherty agreed to accelerate the timetable for the legal challenge to take place, setting the date for the substantive hearing as Friday 6 September.
There will be a preliminary hearing on 4 September, if required, to rule on any points of legal contention between the two sides.
JOHNSON'S CRITICAL WEEK
MPs are currently away from Westminster due to parliament's summer recess, but they are due to return to the House of Commons on Tuesday 3 September.
This means Labour could attempt to topple Mr Johnson's government through a vote of no confidence as soon as the Wednesday or Thursday that week.
Shadow home secretary Diane Abbott recently claimed an early attempt to bring down Mr Johnson's administration "has to be an option", but would not confirm a timetable.
A third challenge to Mr Johnson's hopes of fulfilling his pledge to take the UK out of the EU on 31 October, with or without a divorce deal, is likely to come on 9 September.
Prior to the summer recess, MPs ensured the government is bound by law to provide a report on Northern Ireland on 4 September and then debate it in parliament within five days.
MPs opposed to a no-deal Brexit are expected to use this opportunity to try and secure parliamentary time to force another delay to the UK's departure from the EU by extending Article 50.
A senior government source this week admitted 9 September is shaping up to be a big moment in the looming parliamentary battles between Mr Johnson and Remain-supporting MPs.
One view in Downing Street is that the EU is waiting to see how parliament acts during its first week back before deciding how to respond to Mr Johnson's opening stance on Brexit.
The prime minister has said any Brexit deal must include the abolishment of the controversial Irish border backstop, although Brussels has insisted it must remain in the UK's withdrawal agreement, which - it says - is not up for renegotiation.