NI ministers will continue to have a voice in Brexit talks, insists PM
A snap election will be called if a new Deputy First Minister is not nominated by Monday, the Prime Minister has confirmed.
Theresa May said she was treating the political crisis in Northern Ireland "with the utmost seriousness".
The resignation of Martin McGuinness earlier this week has plunged the political institutions here into crisis.
Speaking at Prime Minister's Questions, Mrs May said the Government was putting in "every effort" to ensure a solution is reached.
And she pledged that Northern Ireland's voice would continue to be heard in Brexit negotiations.
The PM was asked about the consequences of the crisis by SNP MP Angus Robertson.
Mrs May said: "We are obviously treating this with the utmost seriousness."
She said Secretary of State James Brokenshire had urged all parties to work together to resolve the impasse.
"He has spoken to the First Minister and the former Deputy First Minister, and he is urging all parties to work together to find a way forward," Mrs May added.
"I have also spoken to the Taoiseach about this issue, so we are putting every effort into this.
"The legislation says that if, within seven days, we do not have a nomination for a Deputy First Minister, the matter would go to an election."
Mrs May also made clear that events in Belfast would not derail the Government's timetable for leaving the European Union.
She rejected a challenge from Mr Robertson to postpone the start of EU withdrawal talks under Article 50 because, he argued, Northern Ireland would be left without a voice in the process.
Mr Robertson urged the PM not to "plough on regardless" at a time when there may be no Northern Irish ministers available to participate in Joint Ministerial Committee discussions.
The PM's official spokeswoman later said that she understood Stormont ministers would continue to hold their positions in a caretaker role during any election.
The spokeswoman added: "Obviously the situation is in flux and we are doing all we can to try to find a way through, including by the PM speaking to the Taoiseach last night about the situation.
"There is now a window before elections could be called, and we are not going to get ahead of ourselves. We have been clear on the timetable for triggering Article 50 and will be sticking to that.
"We are going to focus on how we can support political stability in Northern Ireland, recognising the progress that's been made and not wanting to put that at risk and engaging with all the parties."
A Labour spokesman said the party wanted a Commons debate on the Government's Brexit negotiating position "as urgently as possible" and before the invocation of Article 50.
The crisis in Northern Ireland "can't be allowed" to derail Mrs May's plan to table Article 50 by the end of March, said the Labour source.
He added: "We are not in any way seeking any such delay.
"We won't do anything to frustrate the passing of Article 50 -we've made that clear time and again - and we don't want delay in it."