Parliament may remain suspended even if Boris Johnson loses a historic Supreme Court case over the five-week prorogation.

Documents submitted on Thursday to the 11 justices hearing the case revealed three possible scenarios in the event the court rules the suspension was unlawful, two of which could see the Prime Minister make a fresh decision to prorogue Parliament.

The other outcome could see the court order that Parliament should be recalled, but Mr Johnson’s lawyers urged the judges to consider the “very serious practical consequences” involved in this option, as it would require a new Queen’s Speech and State Opening of Parliament.

Following the conclusion of the hearing, Boris Johnson - on a visit to Salisbury - declined to rule out suspending Parliament again if he lost the case.

Asked to rule out proroguing Parliament for a second time, Boris Johnson said: "I have the greatest respect for the judiciary in this country.

"The best thing I can say at the moment whilst their deliberations are continuing is that obviously I agree very much with the Master of the Rolls and the Lord Chief Justice and others who found in our favour the other day."

He added: "I will wait to see what transpires."

The court was told the document stated: “A Queen’s Speech, and the State Opening of Parliament which accompanies it, is a significant political, constitutional and ceremonial occasion, which ordinarily involves the sovereign attending in person.

“As the court will be well aware, the proper preparations for a Queen’s Speech are a matter of thoroughgoing importance, including in relation to the content of that speech.

“Extensive arrangements would have to be made, including as to security, to enable this to occur.

“These considerations lead to the need for any order that the court makes, if necessary, to allow for these steps relating to the earlier meeting of Parliament to occur in an orderly fashion.”

Credit: PA Graphics

The court has heard appeals arising out of two separate challenges in England and Scotland – which produced different outcomes – over the Prime Minister’s advice to the Queen to suspend Parliament for five weeks until October 14.

At the High Court in London, the Lord Chief Justice Lord Burnett and two other judges rejected businesswoman Gina Miller’s challenge, finding that the prorogation was “purely political” and not a matter for the courts.

But in Scotland, a cross-party group of MPs and peers won a ruling from the Inner House of the Court of Session that Mr Johnson’s prorogation decision was unlawful because it was “motivated by the improper purpose of stymieing Parliament”.

Mrs Miller is now appealing against the decision of the High Court, asking the Supreme Court to find that the judges who heard her judicial review action “erred in law” in the findings they reached.

Gina Miller arrives at court flanked by police officers. Credit: PA

Her barrister, Lord Pannick QC, told the court on Tuesday that Mr Johnson’s motive for an “exceptionally long” prorogation was to “silence” Parliament, and that his decision was an “unlawful abuse of power”.

Sir James Eadie QC argued on the Prime Minister’s behalf on Wednesday that the suggestion the prorogation was intended to “stymie” Parliament ahead of Brexit was “untenable”.

The justices are also being asked by the Westminster Government to allow an appeal against the decision in Scotland.

Mrs Miller’s case is supported by former prime minister Sir John Major, shadow attorney general Baroness Chakrabarti, the Scottish and Welsh governments and Northern Irish victims’ campaigner Raymond McCord.

Former prime minister Sir John Major is an intervener in the case at the Supreme Court Credit: Yui Mok/PA

On Thursday, the third and final day of the unprecedented hearing in London, Sir John’s QC Lord Garnier told the court his intervention was “nothing to do with the arguments for or against Brexit”.

Lord Garnier said Sir John was of the view that the “inference was inescapable” that Mr Johnson’s decision was “motivated by his political interest in ensuring that there was no activity in Parliament during the period leading up to the EU Council summit on October 17 and 18”.

The Prime Minister advised the Queen on August 28 to prorogue Parliament for five weeks and it was suspended on September 9.

Mr Johnson says the five-week suspension is to allow the Government to set out a new legislative agenda in a Queen’s Speech when MPs return to Parliament on October 14.

But those who brought the legal challenges argue the prorogation is designed to prevent parliamentary scrutiny of the UK’s impending exit from the EU on October 31.

Lady Hale said the court hopes to be able to give its ruling early next week.