Prime Minister Boris Johnson's suggestion he could break the law to force a no-deal Brexit could be challenged in the courts by a cross-party group of MPs, it has been reported.
The House of Lords passed a bill on Friday effectively blocking a no-deal Brexit, paving the way for it to become law.
But, according to The Daily Telegraph, the Prime Minister wrote to Tory members on Friday evening, telling them: "They just passed a law that would force me to beg Brussels for an extension to the Brexit deadline. This is something I will never do."
The BBC reported on Saturday that cross-party MPs, including expelled Conservatives, had sought legal advice and were preparing to go to court "to compel Mr Johnson to seek a delay".
David Lidington, the de facto deputy prime minister when Theresa May was in Downing Street, said it would set a "dangerous precedent" if Mr Johnson opted to disobey the law.
The PM reportedly said he would only have to comply with the Opposition's law blocking no-deal "in theory".
But Mr Lidington, a former Europe minister, told BBC Radio 4's Today programme: "It is such a fundamental principle that we are governed by the rule of law that I hope no party would question it.
"Defying any particular law sets a really dangerous precedent."
The former Cabinet minister said Mr Johnson had convinced him that he still wanted to strike a deal with the EU.
But on Friday, Mr Johnson told reporters he would not entertain seeking another deadline extension from Brussels, as the incoming law, expected to receive Royal Assent on Monday, compels him to if no agreement is in place by October 19.
Asked if he would obey the new law's demand for him to write to EU leaders requesting more time, Mr Johnson said: "I will not. I don't want a delay."
Former Conservative leader Iain Duncan Smith encouraged Mr Johnson to break the law, saying he would be seen as a Brexit "martyr" if judges opted to put him jail for breaching Parliament's terms.
If Mr Johnson fails to carry out the will of Parliament, he risks being taken to court and, if a judge ordered him to obey Parliament, he could be held in contempt and even jailed if he refused, reported The Telegraph.
Mr Duncan Smith told the newspaper: "This is about Parliament versus the people. Boris Johnson is on the side of the people, who voted to leave the EU.
Other ministers are said to take a different approach, however, and think it is time for Mr Johnson to reconcile with the 21 Conservative MPs he sacked this week after they rebelled against him.
The Times reported that senior Government figures want Mr Johnson to "come up with a plan B" and distance himself from Tory Eurosceptics after he was boxed in by the Opposition.
The new law blocking no-deal will rule out an early election before the European Council summit on October 17 as Labour and other opposition parties want the threat of leaving the EU on Halloween to have expired before agreeing to a fresh poll.
Labour, the Liberal Democrats, SNP and Plaid Cymru met on Friday and agreed to block the PM's election request when it is put to the House of Commons again on Monday.
A similar motion was defeated by MPs on Wednesday, failing to make the two-thirds threshold needed to dissolve Parliament.
Meanwhile, research from the British Chambers of Commerce has found a "concerningly high number" of UK businesses are not ready for a no-deal Brexit.
The survey of 1,500 firms found two-fifths had not done a Brexit risk assessment, with the Chambers' director general Adam Marshall saying the research "yet again reinforces the importance of averting a chaotic exit on October 31st".
Mr Johnson made the traditional prime ministerial trip to the Queen's Balmoral estate after visiting Aberdeenshire on Friday.
But the visit will be shorter than expected due to the political turmoil in Westminster.
The PM, accompanied by partner Carrie Symonds, stayed at the castle on Friday night before their return to London on Saturday.
Protests are scheduled across the country over the weekend against Mr Johnson's leadership and Brexit strategy, with demonstrations in London on Saturday.