0930GMT
The decision from the UK Supreme Court is due out at 10:30BST (09:30GMT) and Boris Johnson has said that he will abide by the ruling of the Supreme Court.
However, Boris has not ruled out proroguing Parliament again if he loses.
It is a sad state of affairs in the UK to see the legislature fighting like this, but it is just symptomatic of the deep divide that now exists between 'leavers' and 'retainers' in the UK.
Win or lose, what happens?
If Boris wins it all stays the same and Parliament is suspended until October 14
If Boris loses here is the BBC's take on what happens:
But things could get complicated if the justices decide Mr Johnson acted unlawfully.
In documents submitted to the court, the government said it could see three options if the court ruled against it - and in some scenarios, it might suspend Parliament all over again.
- The court might rule this suspension unlawful, but their reasons might leave open the possibility of proroguing Parliament for the same time period in a different, lawful way
- The judges could decide that the only lawful option is for the prime minister to recall Parliament before 14 October. Lawyers for Mr Johnson said he would comply, but it would require "extensive arrangements" to draw up a new Queen's Speech and get ready for the ceremonial State Opening of Parliament
- The judges could declare the suspension unlawful, meaning Parliament would remain in session as if it had never stopped. The government said it might still be able to consider suspending it again
