The Prime Minister faces the crunch ‘meaningful vote’ on Tuesday which a defeat, as is widely predicted, would plunge the UK into a constitutional crisis. In the event of such an unprecedented situation, it is expected Jeremy Corbyn would try to seize power by pressing for a vote of no confidence in Mrs May. Should the Labour leader win the power struggle he would be given 14 days to form a new government under the Fixed-Term Parliaments Act.
However, if Mrs May refuses to resign, a scenario suggested by Tory MP Andrea Leadsom, Buckingham Palace would be drawn into the chaos.
At the end of the two-week period, the Queen would officially have the power to choose the new prime minister.
She would have to decide whether to dismiss her current ministers and support a Jeremy Corbyn led government or stick with Theresa May.
The situation was suggested by Cambridge academic David Howarth who said it would cause “immense difficulties” for the Queen who tries to stay out of politics.
The Cambridge University professor of law and public policy told The Times: “The Queen would have to step in to dismiss the ministry, a step which, though legitimate, would threaten to bring her into politics.
“The Queen would not know at that point whether a new government could be formed, and her judgement might be proved wrong.
If Mr Corbyn is chosen by the Queen to lead a government it is not a foregone conclusion that he could command a majority in the House of Commons.
In that case, there would be a snap general election in January, just two months before the UK is set to leave the EU.
Professor Howarth said he expects there to be a general election in this eventuality which, while it would give a new leader a mandate, would do nothing to sort out the Brexit crisis.
He said: “What if Jeremy Corbyn failed to win the House’s confidence?
“The result would be a general election in the middle of a national crisis about Brexit, an election highly likely, given the divisions in both main parties, to settle nothing about the cause of the crisis.
“There is a way around these problems.
“The newly rediscovered humble address procedure can be extended beyond asking for documents to making polite suggestions to the Queen about how she might use her other powers, including the power to choose the prime minister.
“The proposal would cause some trepidation at the palace.
“No problem would arise as long as the sitting prime minister is an honourable person.
However, Mr Howarth said if the Queen did use the powers it would be highly controversial but could be the best course of action.
He added: “The basic principle of monarchy follow is that it should always take the least politically controversial course of action and dismissing her current ministers looks controversial.
“But the advantage of the motion is that it relieves the Queen of having to make a judgement about who commands the confidence of the House.
“The current government has lost it and a new one has gained it.
“The motion also avoids the risk of a general election.”