SNP Westminster Leader Angus Robertson has urged the prime minister to postpone triggering Brexit given the situation in Northern Ireland.
The Moray MP said it stood to reason that if there was no assembly or power-sharing executive in place, the UK Government would not be able to properly consult them.
During Prime Minister’s Questions, he asked: “In these circumstances will you postpone invoking Article 50 or will you just plough on regardless?”
Theresa May said the situation following Deputy First Minister Martin McGuinness’ resignation was being treated with the “utmost seriousness”.
But she did not indicate any willingness to delay the end of March timetable.
She told MPs: “It’s still the case ministers are in place.”
If a new deputy first minister is not appointed within seven days of Mr McGuinness stepping down, then elections will be called.
During the period running up to them, the system would revert to one of direct rule.
In that situation, James Brokenshire, as secretary of state, would represent Northern Ireland in any discussions.