Attorney General Geoffrey Cox told Boris Johnson proroguing Parliament was 'lawful'

Attorney General Geoffrey Cox leaves 10 Downing Street

Labour is also calling for Attorney General Sir Geoffrey Cox to make a statement to the Commons when MPs return to Parliament tomorrow after judges ruled that "prorogation" was unlawful and thus void.

Legal advice to the Government is always confidential and the counsel received by Mr Johnson on the issue had not emerged until yesterday.

Leaked extracts of the advice emerged in the texts of conversations between cabinet ministers were released to Sky News.

Supreme Court rules Boris Johnson's Parliament suspension was unlawful

The conversation first emerged in minutes which were released to a Scottish Court, but large sections were redacted.

It has now emerged that in one of the redacted sections, Sir Geoffrey had said it was lawful and anyone disputing this was doing so for political reasons.

The unredacted version of the copy says: "The Attorney General said that his advice on the question of the law is that this was lawful and within the constitution.

"Any accusations of unlawfulness or constitutional outrage were motivated by political considerations. The proposal was compatible with the provisions of the NIEFF 2019."

The Supreme Court has contradicted this position in a unanimous judgement today.

Labour's Kier Starmer, a former Director of Public Prosecutions and Head of the Crown Prosecution Service, said it looks like it "could have been the Attorney's advice".

The shadow Brexit secretary added: "We will need to look into this, but I think the Attorney is gong to have to consider his position, because he's now had a unanimous decision of the Supreme Court, completely the other way indicating the Prime Minister's acted unlawfully.

"At the very least I think the Attorney General needs to be making a statement to Parliament tomorrow.

"I think it's very important that we now see the full legal advice on this."

A spokesperson from the Attorney General's Office said: "The Government acted in good faith and in the belief that it's approach was both lawful and constitutional.

"These are complex matters on which senior and distinguished lawyers have disagreed.

"The Divisional Court led by the Lord Chief Justice agreed unanimously with the Government's legal position, as did the Outer House in Scotland.

"We are disappointed that in the end the Supreme Court took a different view. We respect the judgement of the Supreme Court."

The issue of the lawfulness of the prorogation has unnerved Cabinet ministers.

Julian Smith, the Northern Ireland secretary and the former work and pensions secretary Amber Rudd had pushed Mr Johnson to see a more detailed legal assessment, but this never emerged.

Ms Rudd, who quit Mr Johnson's Cabinet and surrendered the party whip earlier this month over Brexit, said she "regrets" Mr Johnson's strategy on prorogation.

She said she and her colleagues were only told about the plan last minute and, despite being given "personal assurances" from Mr Johnson, they were not shown legal guidance.

Despite personal assurances from the PM, the Cabinet was not shown the legal advice around this prorogation, she tweeted.

"This is an astonishing moment and I regret that the PM, who entered office with such good will, went down this route," she said. "I urge him to work with Parliament to pass a deal."

Ms Rudd later told Sky News the Cabinet was only told about the prorogation on the day that it went ahead.

"One of my cabinet colleagues asked for legal advice and we were assured we would receive it," she said. "I don't know about my other colleagues, but despite me repeatedly asking for it, I never received it."

Ms Rudd suggested Mr Johnson sack his key aide Dominic Cummings, who is believed to be a key figure behind the prorogation plan.

"If I was getting the sort of advice he's been getting, I would certainly consider some people's positions," she said.