Boris Johnson has asked the Queen to suspend parliament for five weeks, in a process called “prorogation”.

The effect is likely to be that MPs who want to stop a no deal Brexit will have very little time to do so before 31 October.

Commons speaker John Bercow has called the decision a “constitutional outrage”. But senior Conservatives, like party chair James Cleverly, have been keen to present the move as par for the course.

So what’s going on?

Is this normal?

The government prorogues parliament pretty frequently — the term simply refers to the process of dissolving one session to make way for another. This normally happens on an annual basis or before a general election.

But as Vernon Bogdanor, Professor of Government at King’s College London, told FactCheck, the length of time proposed in this case is “abnormal”.

House of Commons Library stats reveal that since 2010, the average prorogation has been eight days long. And that figure has been dragged up by a relatively long 20-day period in 2014, which included the European parliamentary elections and the Whitsun recess.

The same report finds that “in the last 40 years Parliament has never been prorogued for longer than three weeks: in most cases it has been prorogued for only a week or less.”

The Queen has approved an order to suspend parliament “no earlier than Monday 9 September and no later than Thursday 12 September” until 14 October. That means prorogation could last up to 34 days.

Dr Asif Hameed, Lecturer in Law at the University of Southampton, told FactCheck that the length proposed by the government here “looks very unusual”.

How is this different to recess?

MPs do not sit in parliament all year round. They have regular breaks — called recesses.

In fact, they were due to have a one for party conference season from mid-September to early October.

Unlike recesses, which parliament can control, a government’s decision to prorogue takes place without the consent of MPs. This prorogation will reduce the time MPs have to debate Brexit and other parliamentary business.

Why is it happening?

In a letter to MPs today, the Prime Minister points out that the current parliamentary session (i.e. the time since the last prorogation) has been unusually long, and that “key Brexit legislation has been held back to ensure it could still be considered for carry-over into a second session”.

These are his stated reasons to justify proroguing parliament — although they don’t quite explain why the suspension needs to be so lengthy.

Dr Hameed points out that “there is a standing worry that prorogation could be used for partisan political reasons. There are concerns that the Government is acting in a partisan way, given (1) the timing and also (2) the length of the prorogation period.”

He also notes that “the Government is aware that opposition parties are openly considering legislation to block a no-deal Brexit and also whether/when to bring a no confidence motion under the Fixed-term Parliaments Act 2011.”

That second point, he says, “would be particularly concerning constitutionally — namely, a Government moving to prorogue Parliament when it is aware that it may be facing a no confidence motion”.

Can it be stopped?

Professor Bogdanor tells us that MPs cannot stop parliament being prorogued.

However, Dr Hameed raises a possible alternative: that MPs could try to block the move by legislating — perhaps through a “one-line Act of Parliament” or by bringing a no confidence motion to topple the government — once Parliament reconvenes on 3 September.

Nevertheless, he points out that “the timing presents significant difficulties” for opposition MPs, who would also need to wrest control of the parliamentary timetable from the government.

The Queen has a role in all of this — it’s technically up to her to grant the Prime Minister permission to prorogue parliament in the first place.

But both Professor Bogdanor and Dr Hameed are in agreement: while she could technically say no, doing so would be a major breach of her constitutional requirements to remain neutral and take the advice of her Prime Minister.

What about a legal challenge?

Professor Philip Norton of Hull University, who also sits in the House of Lords as a Conservative peer, explained to FactCheck: “In terms of the formal process, the correct procedures are being followed” because “prorogation is a prerogative act of the Crown and the Queen accepts the advice of her ministers as to when to prorogue”.

That means if there were to be a court battle, Professor Norton says “the legal challenge may be to seek judicial review of the Prime Minister’s advice.” Professor Bogdanor points out that such a case that would be “unprecedented”.

And there’s a further complication: it’s not clear whether a legal challenge could overturn the prorogation in time to make a real difference to the Brexit process.

Labour’s shadow attorney general Shami Chakrabarti has reportedly advised her party leader that the courts “might well even” allow parliament to continue sitting while a case was moving through the courts. Dr Hameed told FactCheck that “an interim order could require that Parliament continue to sit.”

But Professor Bogdanor disagrees: “In my view, parliament would not be sitting during the time of the challenge. The advice [to prorogue parliament] would be lawful unless and until the courts ruled otherwise.”

If that’s the case, the courts would have to decide on any legal challenge very swiftly in order to make a difference in time. Professor Norton thinks this is plausible, reminding FactCheck that “The courts can, when they see fit, move quickly.”

Other controversial prorogations

This isn’t the first time eyebrows have been raised over a prorogation.

In 1948, Labour Prime Minister Clement Atlee prorogued parliament to get around opposition to the Parliament Bill, which intended to limit the powers of the Lords.

Prorogation was a short-term tactic which created an extra session of parliament, speeding up the process by which the Commons can override the Lords. The situation was rather different to today’s, as government policy had a majority in the Commons.

And in 1997, Conservative Prime Minister John Major prorogued parliament 19 days before it would have been dissolved anyway to hold a General Election. Critics widely accused Major of misusing prorogation powers to avoid the publication of a damning report into Conservative MPs taking cash for questions.

Professor Norton summarises the current position thus: “Under the Westminster system of government, the government is in the driving seat. There is a tussle now for the steering wheel.”