His opponents claim he did so to silence opposition to his plans to take Britain out of the European Union on October 31, with or without a divorce deal with Brussels.
Earlier on Friday, the courtroom played host to a remarkable sight: that of a former British Prime Minister making a case against the incumbent in the country's highest court.
Parliament is prorogued about once a year so that the government can launch a new program of legislation with a formal State Opening of Parliament and a policy speech read by Queen Elizabeth II.
Supreme Court will deliver its verdict next week in a landmark case on Prime Minister Boris Johnson's decision to prorogue Parliament.
The U.K.'s decision to leave the European Union has raised concern that Japanese firms will shift operations elsewhere if tariff-free trade ends with the rest of the European bloc.
Scotland's highest civil court called the suspension of parliament "unlawful", but the High Court in England said it was not a matter for judges.
The judges are concurrently additionally listening to the United Kingdom authorities's attraction towards a contradictory ruling by Scottish Excessive Courtroom judges, who had declared the Parliament suspension "unlawful".
Depending on the legal basis upon which the judges reach their conclusions, Parliament may have to reconvene if Mr Johnson - who has refused to rule out a second suspension - loses the case.
Government lawyer Richard Keen said the prime minister's opponents were "inviting the courts into forbidden territory and into what is essentially a minefield".
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Harsh Vardhan Shringla made these comments while addressing an event "India on the Hill: Charting a Future for Indo-US Relations". Modi has previously addressed similar gatherings at Madison Square Garden in NY and the SAP Center in San Jose.
Johnson says he will not seek a delay under any circumstances, though it's not clear how he could avoid it.
"That would be a remarkable position for the courts to endorse", argued Major, who was represented in the court by barrister Lord Edward Garnier.
Major questioned why Johnson would not explain his motivations in writing.
Before the suspension, Johnson suffered one defeat after another in parliament, where he has no majority.
Gina Miller has said her case is much more important than even Brexit.
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It is the main body for cross-border cooperation between the governments of Northern Ireland and the Republic of Ireland.
"Isn't it odd that nobody has signed a witness statement to say 'this is true, these are the true reasons for what was done"?' he asked.
"Despite repeated requests nobody has been prepared to do so".
At the close of the unprecedented hearing yesterday, the court's president Lady Hale said the judges hope to give their decision early next week.
It comes as Ireland's Foreign Minister, Simon Coveney rubbished what he called "spin" over Brexit "progress" and called on all sides to be honest that "we are not close to a deal right now".
The case has attracted huge public interest.
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Unlike most British court proceedings, Supreme Court sessions can be broadcast, and this one will be streamed live online.