Boris Johnson could face attempts to have him cross-examined about his government's "candour" on its Brexit strategy, the High Court has heard.
Counsel for a victims campaigner challenging any no-deal withdrawal from the EU raised the possibility of seeking to have the Prime Minister give evidence at proceedings in Belfast.
The development came during preliminary discussions in the legal action brought by Raymond McCord.
Mr McCord claims that taking the UK out of Europe on October 31 without an agreement would breach the Good Friday Agreement and threaten the Northern Ireland peace process.
In court on Thursday, government lawyers argued that the passage of a bill aimed at stopping a no-deal Brexit meant the the case no longer required be heard urgently on Friday.
Referring to the developments at Westminster, Tony McGleenan QC contended, "It changes entirely the paradigm."
But his opposite numbers questioned whether Downing Street would even abide by the law if, as anticipated, it gains royal assent early next week.
Ronan Lavery QC - representing Mr McCord - said, "I'm sorry to have to make that point, My Lord."
Alluding again to senior Tory figure Michael Gove's refusal to rule out the possibility of ignoring any such legislation, Lord Justice McCloskey responded, "Well, there's a certain evidential foundation."
Mr Lavery insisted the political circumstances remain so fluid that the government may do something unexpected to ensure the UK exits by the current October 31 deadline.
"There's a very real issue of candour," he stressed.
Suggesting a direction may be sought to secure affidavit evidence on the administration's policy, the barrister added: "Any any deponent be required to attend for cross-examination, and that may be the Prime Minister."
Mr McCord's case is one of three applications for judicial review being heard in Northern Ireland.
Barry Macdonald QC - representing another member of the public granted anonymity - said his client's challenge was to alleged decisions to proceed to a no-deal Brexit and pursue policies which will inevitably lead to a hard border in Ireland.
He told the court Mr Johnson has vowed not to comply with a requirement to seek a Brexit extension.
"That raises the question whether or not some other ruse is anticipated," Mr Macdonald said.
"This is a government that clearly does not operate within constitutional norms, or respect convention.
"We can't rely necessarily on the mechanism devised by parliament... if it becomes law on Monday."
Adjourning following submissions, the judge confirmed that opening arguments are still due to get underway on Friday.