Thanks for following our live coverage of the final day of the Supreme Court hearing.

President of the Supreme Court Lady Hale has said it hopes to give its ruling early next week.

The SNP's Joanna Cherry says she is "cautiously optimistic" the Supreme Court will rule that Boris Johnson's decision to prorogue Parliament was unlawful.

The MP led the successful legal challenge against prorogation in Scotland, which the government is appealing.

Speaking to reporters outside the court she said: "This is a matter of legality. This is a matter of upholding democracy and a matter of upholding the rule of law."

She wants the court to be "as clear as they possibly can about the consequences of their decision", she adds, if they rule against the government, to leave the prime minister with "no room for any more dirty tricks".

BBC legal correspondent Clive Coleman says the case has "stress-tested" our unwritten constitution "to the very limit".

"If we had a written constitution that said 'two weeks proroguing is fine but five weeks isn't' we wouldn't be here today

"I think it's shown, really, the tectonic plates of the constitution grinding up against each other", he says.

But, he adds, it all comes down to the decision of 11 people - the Supreme Court justices.

"We're in fascinating territory because if they do declare the PM has acted unlawfully then we really have to look at the nature of that declaration to see where things go from there.

Whether its a case of MPs simply filing back in at the invitation of the Speaker, or whether that has to be activated by the government - quite how that is all going to shake down remains to be seen.

Dominic Casciani
Home Affairs Correspondent

Lady Hale, president of the Supreme Court, sums up the tension of three days of potentially historic debate: “None of this is easy."

She says: “I must repeat this case is not about when and what terms the UK leaves the EU. We are solely concerned with the lawfulness [of prorogation]."

Lady Hale says they hope to rule early next week.

Lady Hale responds to Lord Pannick by saying that Lord Pannick should assume that the court will make its decision "as soon as it humanly can".

Dominic Casciani
Home Affairs Correspondent

Lord Pannick is trying to insulate the judges from a “political" decison.

He argues that a simple legal declaration of unlawfulness would be enough for the Speakers of the Commons and Lords to know what to do next politically.

It keeps the judges out of politics.

Dominic Casciani
Home Affairs Correspondent

Lord Pannick says the government has no case when it claims the court cannot turn to any kind of legal measure or standard to assess whether prorogation was unlawful.

He says: "It applies the relevant legal principle - the supremacy of Parliament - to the circumstances of the case... The length of the prorogation, the reasons given, the adverse effect on Parliamentary scrutiny.

"And having done that, the court asks itself in light of all those circumstances [and giving Mr Johnson some benefit of the doubt] whether the PM's decision is beyond the scope of his powers. This is standard business in judicial review.”

Lord Pannick adds: “The remedy we seek is that the prime minister's advice to Her Majesty was unlawful. We respectfully ask the court to make such a declaration as soon as possible because time is of the essence."

He asks the court to ensure that its judgement ensures that Parliament can sit NEXT WEEK.

Lord Pannick says: "This prorogation has prevented Parliament from carrying out its scrutiny of the executive at a time when the constitutional principle of the executive being answerable to Parliament is of vital importance."

If the court does not feel that it can find the prime minister had some "malign" intention, the suspension could still be found unlawful by looking at its effect and impact, Lord Pannick says.

BBC home affairs correspondent Dominic Casciani says: "I'm betting this is a crucial matter for the justices."

Lord Pannick tells the Supreme Court that by ruling that this prorogation is unlawful it would help protect the separation of powers - between the government, Parliament and the courts - by ensuring government cannot separate itself from Parliamentary scrutiny.

Joanna Cherry, the SNP MP who was part of the case against Parliament's suspension in Scotland, praises Lord Pannick's "sweeping up operation" in response to the government's case.

She also addresses a question some readers might have: why don't the Scottish campaigners get a right of reply?

The answer is that they won their case in the Scottish courts, she says, so they are not the party that is appealing to the Supreme Court. Instead, the government is appealing against their victory.

In the English case, it's the other way around, after the government won its case initially.

Earlier, we mentioned that documents submitted for the government outlined options if it loses the case.

One suggested that the judges might rule suspending Parliament was unlawful, but leave open an option to prorogue it for the same period in a lawful way.

There are two further options outlined. The court could find that suspension was unlawful and that recalling Parliament before 14 October was the "only option lawfully open to the prime minister".

In this scenario, the document says Mr Johnson would comply, but that the court could also make a "mandatory order".

But it said there would be "very serious practical consequences", because recalling Parliament would require a meeting of the Privy Council and a new Queen's Speech - where the government sets out its legislative programme.

"Extensive arrangements would have to be made," it says.

The last option considered is that the court could rule the suspension was unlawful, and therefore it was never prorogued and remains in session.

But Mr Johnson's lawyers say that it may still be open for the prime minister to suspend Parliament again, depending on the court's reasoning.

Lord Garnier QC has set out the arguments made in Sir John Major's submissions at the Supreme Court hearing.

Lord Keen argues that prorogation "for no rational reason" prevents Parliament from holding the government to account for an "exceptional length" of time.

He says the suspension also prevents some "very important bills" from passing through Parliament.

Lord Pannick QC, for campaigner Gina Miller, says the "central issue" is why was Parliament prorogued for five weeks - longer than any period for the last 40 years.

The government says that because this period covers party conference season the prorogation only covers a matter of days.

But Lord Pannick says Parliament decides whether or not to have a recess - during which Parliament does not sit - for party conferences.

He says there was "no coherent answer" by Lord Keen, the government's lawyer, about why there was a need to prorogue Parliament before the party conference season, which begins in early October.

Image source, UK Supreme Court

Lord Keen, representing the government, has now finished speaking.

Now it's Lord Pannick QC, the lawyer representing campaigner Gina Miller.

Yesterday Aidan O'Neill, lawyer for the Scottish campaigners against suspending Parliament, alluded to "dirty tricks" and said the "mother of parliaments" was "closed down by the father of lies".

He said documents submitted by the government should not be treated as "gospel".

But today Lord Keen has objected to the suggestion that the government's evidence needs to be treated with skepticism.

He calls the language used "discourteous and incendiary", BBC Scotland political correspondent Andrew Kerr notes.