Boris Johnson could face two more legal showdowns to force a Brexit extension should he fail to secure a deal by October 19.
The Prime Minister has consistently said he will take Britain out of the European Union on October 31 with or without a deal, however the Benn Act compels him to request an extension.
Scotland’s highest civil court is set to hear two cases within five days that may put further pressure on Mr Johnson to follow the law.
The first - led by businessman Vince Dale, SNP MP Joanna Cherry QC and Jolyon Maugham QC - would ask for a court order that ensured the Prime Minister request an extension should he refuse to abide by the Benn Act.
The second would ask Scottish judges to use their unique power of “nobile officium” to allow a court official to sign the extension letter should Mr Johnson refuse.
Ms Cherry said the Prime Minister “cannot be trusted”.
“If Boris Johnson tries to defy the law and defy both the Holyrood and Westminster Parliaments by crashing out of the EU without a deal - then we are calling on the Scottish courts to uphold the law,” he said.
The Prime Minister told the Commons on Thursday he had made a “genuine attempt to bridge the chasm” with the EU and it was now up to them to compromise.
However, his “two borders” suggestion for Northern Ireland has received a frosty reception from Europe, with European Council president Donald Tusk saying he was “unconvinced”.
And Irish premier Leo Varadkar said he did not understand how Mr Johnson believed Ireland and Northern Ireland could operate under different customs regimes without checkpoints.
“It's very much the view of the Irish government and the people of Ireland, north and south, that there shouldn't be customs checkpoints or tariffs between north and south,” he said.