Boris Johnson could face attempts to have him cross-examined about his government's "candour" on its Brexit strategy, the High Court heard yesterday.
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.
He 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 yesterday, Government lawyers argued that the passage of a bill aimed at stopping a no-deal Brexit meant 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, 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.
He also claimed there is a "very real issue of candour" in terms of the Government's approach to Brexit, and suggested that Prime Minister Boris Johnson may be required to attend for cross examination.
Mr McCord's case is one of three applications for judicial review being heard in Northern Ireland.
Barry Macdonald QC - who is representing another member of the public who has been granted anonymity - said his client's challenge was against alleged decisions to proceed to a no-deal Brexit and pursue policies which will inevitably lead to a hard border in Ireland.
Mr Macdonald told the court Mr Johnson has vowed not to comply with a requirement to seek a Brexit extension.
Opening arguments are due to get underway today.