The attorney general has apologised for making a "joke" about domestic violence during a fiery defence of Boris Johnson's decision to suspend parliament.

Geoffrey Cox came under fire during an urgent question on his legal advice on prorogation, when he compared being asked when he knew the advice was "not true" to being asked the loaded question "when did you stop beating your wife?"

Labour MP Emma Hardy told the senior Tory not make a "joke" of domestic violence and urged him to "moderate his language", as opposition MPs could be heard describing his comments as "disgusting".

Ms Hardy said the words would cause particular offence, as the future of a crucial domestic violence bill was thrown into doubt by the prorogation of parliament.

Mr Cox apologised for his comments, saying it was a well-known phrase used by lawyers in relation to a "cross-examination technique of asking a question that presumes the premise".

The attorney general had been responding to a question from Labour MP Clive Efford, who asked: "When was it that he first became aware that the advice that was given to Her Majesty the Queen, the Speaker of this House and this House itself about the reasons for prorogation, and that those reasons were not true?"

He replied: "That is, if I may say so, what we used to call in advocacy terms a 'when did you stop beating your wife?' question - the reality is I don't accept the premise of the question.

"There is no question that the Supreme Court found in any way that any advice that had been given was consciously or knowingly misleading."

The row came after Mr Cox made a bombastic appearance in the Commons, where he declared parliament was "dead as dead can be" and demanded a general election.

'This parliament is a disgrace!' Geoffrey Cox says opposition parties are 'too cowardly' to vote for an election

The senior Tory had been summoned to answer questions about the legal advice he gave Mr Johnson over prorogation after the Supreme Court ruled the move was unlawful.

Mr Cox insisted that the government had acted "in good faith" when it suspended parliament, which the prime minister said was necessary to prepare its domestic legislative agenda.

However opposition MPs were outrages as they believed it was an attempt to dodge scrutiny on his Brexit plans.

As tensions between the government and the opposition ramped up, Mr Cox warned MPs they have "no moral right" to sit on the green benches of the House of Commons.

Supreme Court verdict: Boris Johnson prorogation unlawful Show all 16 1 /16 Supreme Court verdict: Boris Johnson prorogation unlawful Supreme Court verdict: Boris Johnson prorogation unlawful The Supreme Court has ruled against Boris Johnson by declaring his government unlawfully shut down parliament for five weeks EPA Supreme Court verdict: Boris Johnson prorogation unlawful Lady Hale handed down the historic verdict, hailed by opposition MPs and anti-Brexit campaigners. She said all 11 judges were unanimous in deciding that the case is “justiciable”, so the government loses that part of the argument. “The court is bound to conclude therefore that the decision to advise Her Majesty to prorogue was unlawful because it had the effect of frustrating or preventing the ability of Parliament to carry out its constitutional functions.” EPA/Supreme Court Supreme Court verdict: Boris Johnson prorogation unlawful Gina Miller and her team react outside the Supreme Court are the verdict. She said: “Today is not a win for any individual or cause. It is a win for Parliamentary sovereignty, the separation of powers and independence of our British courts. Crucially, today’s ruling confirms that we are a nation governed by the rule of law, laws that everyone, even the Prime Minister, are subject to." PA Supreme Court verdict: Boris Johnson prorogation unlawful A person dressed as a caricature of British Prime Minister Boris Johnson in a prison uniform stands outside the Supreme Court AP Supreme Court verdict: Boris Johnson prorogation unlawful Labour leader Jeremy Corbyn called for Mr Johnson to “consider his position” following the landmark decision, while Lib Dem leader Jo Swinson said he was “not fit to be prime minister” Getty Supreme Court verdict: Boris Johnson prorogation unlawful Scottish National Party (SNP) Westminster leader Ian Blackford raises his arms as he comes outside. He said: "This is an absolutely stunning judgement by the Supreme Court today." He went on to say, "we all want to get back to work, and quite frankly, on the back of this, Boris Johnson must resign immediately." AFP/Getty Supreme Court verdict: Boris Johnson prorogation unlawful Crowds outside celebrated the verdict AP Supreme Court verdict: Boris Johnson prorogation unlawful Delegates at the Labour party conference applaud after hearing the news AFP/Getty Supreme Court verdict: Boris Johnson prorogation unlawful Speaker John Bercow said MPs must now “convene without delay” and confirmed the Commons would return at 11.30am on Wednesday AFP/Getty Supreme Court verdict: Boris Johnson prorogation unlawful Gina Miller said: "“As a result of this judgment, Parliament is open, it was never prorogued. I urge MPs to get back to work immediately.” AP Supreme Court verdict: Boris Johnson prorogation unlawful MPs Anna Soubry, Liz Saville Roberts and Caroline Lucas, together with SNP leader Ian Blackford, react. Green MP Caroline Lucas has said the Supreme Court’s decision is “just the start” Reuters Supreme Court verdict: Boris Johnson prorogation unlawful “The UK deserves a Prime Minister and a Government who act with honesty, integrity and in a manner consistent with our constitution, at all times." AFP/Getty Supreme Court verdict: Boris Johnson prorogation unlawful Anti-Brexit supporters react as they gather outside the Supreme Court in London, Tuesday, Sept. 24, 2019 as it makes it's decision on the legality of Prime Minister Boris Johnson's five-week suspension of Parliament. (AP Photo/Frank Augstein) Frank Augstein AP Supreme Court verdict: Boris Johnson prorogation unlawful The SNP’s Joanna Cherry QC says: “Boris Johnson’s position is untenable and he should have the guts to resign.” PA Supreme Court verdict: Boris Johnson prorogation unlawful epa07865617 Protesters react outside the Supreme Court after the result of a hearing on the prorogation of parliament, in London, Britain, 19 September 2019. The Supreme Court ruled that the suspension of parliament by British Prime Minister Boris Johnson was not lawful. EPA/NEIL HALL NEIL HALL EPA Supreme Court verdict: Boris Johnson prorogation unlawful Tom Tugendhat MP returned to the chamber in the House of Commons within minutes of the Supreme Court ruling PA

He told the Commons: "This parliament has declined three times to pass a Withdrawal Act, to which the opposition, in relation to the Withdrawal Act, have absolutely no objection.

"Then we now have a wide number of this House setting its face against leaving at all, and when this government draws the only logical inference from that position, which is we must leave therefore without any deal at all, it still sets its face, denying the electorate a chance of having its say in how this matter should be resolved.