No-deal Brexit: Can MPs overrule the new prime minister?
(30 days later)
One of the hot topics in the race to succeed Theresa May as prime minister is whether a new leader could make the UK leave the European Union without a deal, against the wishes of MPs.
The question of how the UK will leave the European Union (EU) is very much alive, as Conservative Party members choose a new prime minister. Do MPs have the power to stop a no-deal Brexit if the new prime minister wants one?
Even though most MPs oppose a no-deal strategy, some argue the next government could go ahead without the consent of Parliament.
What is no deal?
A row broke out after Conservative leadership candidate Dominic Raab said he would be prepared to prorogue Parliament to make sure the UK leaves the EU on 31 October.
Tory leadership contender Boris Johnson says he is not bluffing about leaving the EU on 31 October - even if it means walking away without a deal.
What is prorogation?
His opponent, Jeremy Hunt, says he will decide by the end of September whether there is a "realistic chance" of reaching a new deal. After that, he will prepare to leave without one.
At the end of every parliamentary session - which usually lasts around a year and starts with the State Opening of Parliament and a Queen's Speech - Parliament is "prorogued" by the Queen.
A no-deal Brexit means the UK would immediately leave the EU with no agreement in place about the "divorce" process - or how they separate.
It essentially closes Parliament and ends the process of current legislation until a new session begins. Although it is technically at the Queen's "command", in practice it is the government's decision.
Overnight, the UK would leave the single market and customs union - arrangements designed to help trade between EU members.
How could it be used to stop MPs forcing the government's hand?
Many politicians and businesses say this would damage the economy.
If a new prime minister is concerned about MPs blocking the UK's exit from the EU, they could advise the Queen to prorogue Parliament, therefore sending MPs away so that they can't do anything to scupper Brexit.
Others say the risks are exaggerated.
It would be unprecedented in modern times to use this power for political reasons, rather than to end a session in preparation for a new Queen's Speech.
Theresa May couldn't persuade her own MPs to support her agreement with the EU, which would have avoided no deal. That's why she resigned.
One leadership candidate, Rory Stewart, has said to do so would be "illegal, unconstitutional, undemocratic and it wouldn't work".
Unless the new prime minister can get their own Brexit plan passed, the UK will face the prospect of leaving with no deal on Halloween.
Without prorogation, can MPs stop no deal?
The alternative would be extend the deadline again - or cancel Brexit altogether.
Some leadership candidates are more relaxed about leaving without a formal deal than others.
How could a new prime minister make no deal happen?
Esther McVey has said politicians should "actively embrace" leaving without a deal and doesn't think Parliament can stop this.
In theory, unless a new plan is agreed, the new prime minister does not need to do anything for a no-deal Brexit to happen.
But fellow Conservative MP Ken Clarke rejects this idea, saying it would be a "constitutional outrage" for a prime minister to attempt to leave without a deal against the will of Parliament.
This is because the UK's departure on 31 October is already written into law. The prime minister could just run the clock down.
But who is right? Can Parliament step in to block a looming no-deal exit? Or is the power solely in the hands of the new prime minister?
But it is not as simple as this.
What's the law?
Most MPs in the UK Parliament are against leaving without a deal. And they could try to stop it from happening.
Currently, the default position is that the UK will leave the EU on 31 October. So if nothing changes, Brexit will happen regardless of whether there is a deal or not.
The prime minister could try to get round this problem by closing Parliament in the run-up to Brexit day. This would deny MPs an opportunity to block no deal.
To change this, you have to change the law.
It's called prorogation and would be a highly controversial move.
The government controls the timetable in Parliament, so the new PM could avoid opportunities for Parliament to force their hand, just by doing nothing.
What can MPs do to stop no deal?
This would mean that MPs wanting to block a no deal - perhaps by changing the exit date - would not have the opportunity to force the PM to do anything. But what are the options open to MPs who want to scupper the plans of a leader who is pursuing a no deal?
If there is no attempt to close Parliament, MPs have a few options.
Take control of Parliament
Hijack new laws to avoid no deal
In March and April this year, a group of MPs took control of the parliamentary timetable, ultimately passing a piece of legislation against the wishes of the government. The new law - dubbed the "Cooper/Letwin Bill" - forced the government to seek a delay to Brexit.
If the government tries to pass new laws, MPs could try to make changes that would force the government's hand.
But it would be hard for MPs to do this again.
For example, they could add new clauses that would push back the Brexit deadline.
Backbenchers were able to seize control of Parliament in March by attaching an amendment to a government motion, which was seen as binding by the Speaker of the House, John Bercow.
The main obstacle is whether the government has to introduce any new laws at all.
The motion was legally required after the failed meaningful vote.
A new prime minister might want to pass legislation to help prepare the UK for a no deal, for example in trade. But it is up to them whether or not to do so.
So if there is no meaningful vote, there is no motion, and there is no way to amend it and take control.
Hold a vote of no confidence to get rid of the government
This is the argument supported by Ms McVey, who told the BBC's Victoria Derbyshire programme: "When you bring something forward to the floor of the House, it's only then things can be amended… and then you can alter the journey and the course. Well, I wouldn't be bringing back the withdrawal agreement, so there would be nothing you could amend to alter it."
Seen by some as the "nuclear option", MPs have the option to vote out the government.
A vote of no confidence
If most MPs oppose the government in a vote of no confidence, the prime minister is out.
This is the most straightforward option.
Under rules introduced in 2011, such a vote either gives a different group of MPs a go at forming a government or leads to a general election.
It is a binding motion that would determine whether the current government has the support of MPs. If the PM loses the vote, there would be 14 days for someone to try and form a government. If no government is formed, it is back to the country for a general election.
Labour says it will call for a vote of no confidence once the new prime minister is in place.
Legislation
Jeremy Corbyn, its leader, did this in January - but Theresa May comfortably saved her job.
Any attempt to pass laws would give MPs the opportunity to force the government's hand and ultimately rule out leaving without a deal. For example, if a minister puts forward a business motion - which sets the timetable for a piece of legislation - an MP could amend it and take control of Parliament on another day, perhaps to pass a bill.
The big question is whether, if the UK is heading for no deal, enough Conservative MPs would vote to dismiss their own leader.
To avoid this, the government might have to decide not to bring any legislation to the Commons between July and October - not even laws that could help prepare for a no-deal scenario.
Express the will of Parliament
Emergency debates
MPs sometimes vote on things to show their opinion, even if that doesn't lead to new laws.
Backbench MPs - with the help of the Speaker of the House - can force a debate onto the timetable on matters of emergency. These are usually seen as non-binding.
They could do this to express their opposition to a no-deal Brexit.
However, Mr Bercow has recently suggested they could be used to force the government to take a particular course of action.
It wouldn't force the prime minister to do anything but it could put him under pressure.
He said in March: "The opportunities are fuller than has traditionally been acknowledged or taken advantage of by Members of the House of Commons."
John Bercow, the speaker of the House of Commons, has hinted he could help MPs find ways to force the government's hand, such as emergency debates.
Political pressure
This might rely on some creative interpretation of the rules.
Regardless of whether the procedure allows it, a prime minister going against the will of Parliament, and avoiding scrutiny by not bringing anything to Parliament, risks a breakdown of political trust.
Keep Parliament open
This is a point argued by Jack Simson Caird of the Bingham Centre for the Rule of Law, who argues that, even if Parliament cannot stop a leader pursuing a no deal, "realistically, the country is ungovernable if the government decides to completely ignore Parliament".
Of course, all of the above depends on Parliament being kept open.
Boris Johnson has so far refused to rule out giving MPs a forced break - so they can't force his hand.
Some opponents are looking for ways to block him from doing so.
Conservative MP Dominic Grieve tried to use government legislation to block any closure of parliament in the run up to Brexit.
However, he failed to pass amendments which would have legally bound the future PM to keep parliament open in October.
The government's tiny majority in the Commons means these issues are often decided on a majority of one or two votes.
