BORIS Johnson has been urged to submit a sworn statement under oath to a Scottish court, setting out his reasons for suspending Parliament.

Aidan O'Neill QC, a lawyer acting for a cross-party group of 76 MPs and peers seeking to prevent the Prime Minister from proroguing Westminster, made the suggestion at the Court of Session in Edinburgh.

It came after an attempt to stop Mr Johnson suspending Parliament suffered a temporary setback.

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Lord Doherty rejected an emergency bid asking him to suspend the order proroguing Parliament and issue an interim interdict – similar to an injunction in England and Wales – to stop ministers or anyone else “from seeking by any means to advise the Queen to prorogue the Westminster Parliament” prior to October 31.

However, he did not give a ruling on whether the move to suspend Parliament is lawful, and moved a full hearing on the issue forward to Tuesday next week, rather than Friday.

He said: "It is in the interests of justice that it proceeds sooner rather than later."

Mr Johnson is facing a series of legal challenges over his decision to suspend Parliament for up to five weeks, ahead of a Queen's Speech on October 14.

Former Prime Minister Sir John Major has said he will join a separate action being brought by campaigner Gina Miller, which will be heard at the High Court in London on September 5.

He suggested his experience in Number 10 could assist the High Court in deciding whether Mr Johnson's actions in proroguing Parliament are lawful. Liberal Democrat leader Jo Swinson is also seeking to join the case.

Meanwhile, legal action at the High Court in Belfast has been adjourned until next week.

In Scotland, a cross-party group of politicians, led by SNP MP Joanna Cherry, want the Court of Session to rule that suspending Parliament is unlawful and unconstitutional.

Mr Johnson's decision is seen as an attempt to thwart MPs seeking to block a no-deal Brexit.

Speaking outside the Court of Session, Ms Cherry called on the Prime Minister to "tell the truth" and have the courage of his convictions.

She said: "If he believes that he has a good case for prorogation, he should have the guts to swear an affidavit."

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Ms Cherry has already submitted an affidavit insisting that suspending Westminster would not give MPs enough time to debate Brexit.

She said she anticipated the case going all the way to the UK Supreme Court.

Mr O'Neill previously argued the decision to prorogue Parliament for five weeks ahead of Brexit is an abuse of power unprecedented since the age of the Stuart kings.

He told the court the UK is a constitutional democracy ruled by law, adding: “We do not live in a totalitarian state.”

However, Lord Doherty said he was "not satisfied that it has been demonstrated that there's a cogent need for interim suspension or interim interdict to be granted at this stage".

He said both sides will have the opportunity to present their arguments at a full hearing next week, meaning an immediate ruling is unnecessary.

And he said his refusal to grant an interdict was not a judgement on whether prorogation is lawful.

Nick McKerrell, a lecturer in law at Glasgow Caledonian University, said Mr Johnson could face cross-examination if an affidavit is sought.

He said: "This is not automatically granted though and it would be yet another extremely unusual process if the court agreed to that."

Roddy Dunlop QC, acting for the UK Government, urged Lord Doherty to hold the full hearing on Wednesday next week, rather than Tuesday, due to prior commitments in the legal team. This was rejected.

Ian Murray, a Labour MP and one of the cross-party group seeking to stop Mr Johnson's latest move, said the verdict meant "a full hearing has been fast-tracked to next week, which is now the most important week in modern British history".

He added: “It is disappointing that we have to go to the courts to protect British democracy, but Boris Johnson’s attempt to silence the people’s representatives cannot go unchallenged."

A UK Government spokeswoman said: “As we have set out, the government needs to bring forward a strong domestic legislative agenda, and MPs are not prevented from scrutinising our withdrawal from the EU.

“We are glad the Court found against the interdict - there was no good reason to seek one, given the full hearing is due to take place next week, and the process of bringing the session to an end will not start until the week commencing 9 September.”