LONDON — As a largely ceremonial head of state, Queen Elizabeth II is not accustomed to being dragged into the messy heart of British politics. But on Wednesday, that's exactly where she found herself.

At a secretive meeting in Balmoral Castle, the fairytale royal residence in Scotland, ministers sent by Prime Minister Boris Johnson asked the queen, 93, to suspend Parliament for a month.

The world's longest serving living monarch had little choice but to agree to "prorogue" Parliament, the formal name for the suspension. And this has triggered what many across the political spectrum say is an unprecedented constitutional crisis that threatens the values of British democracy.

Johnson says he made this request because the current parliamentary term has gone on too long, and he wants to launch a "bold and ambitious domestic legislative agenda."

Few buy that.

Most believe he wants to make sure lawmakers don't come back from summer recess with enough time to thwart his plans for Brexit, which is currently due to happen on Oct. 31. Some think he wants to goad them into triggering a general election, which he would likely fight as the populist champion of Brexit.

Either way, Johnson stands widely accused of exploiting a huge gray area left by the U.K.'s lack of a single constitutional document, and of using the supposedly apolitical queen as a tool to achieve his short-term Brexit goals.

"To ask her to prorogue in these circumstances is, in effect, an abuse of executive power," said Meg Russell, a professor and director of the Constitution Unit at University College London.

Members of Johnson's own party and beyond called the move a "constitutional outrage" and "profoundly undemocratic."

John Major, a former Conservative prime minister, has compared Johnson to Charles I, the 17th century king whose suspension of Parliament led to the English Civil War and ultimately his own beheading.

What's the queen got to do with it?

In the U.S., President Donald Trump is the head of state and the head of the government. In the U.K., however, Johnson is the head of the government and the queen is the head of state.

The power resides in the government and the Houses of Parliament. In normal circumstances, the queen's role is mostly ceremonial.

Paul Delaroche's "Charles I Insulted by Cromwell's Soldiers." The National Gallery / via Reuters file

One of her functions is to open and close Parliament with the passing of every legislative cycle, which normally lasts a year. These occasions are ablaze with velvet robes, wigs and all the other paraphernalia associated with the British ruling classes.

"Because we are a constitutional monarchy, officially the queen has to make some decisions with regard to Parliament and government, and has to therefore take advice from the prime minister," said Tim Bale, a politics professor at Queen Mary University of London.

But — years-deep into a Brexit turmoil that has gripped most aspects of political and social life — Britain is a long way past normal.

Whereas the queen normally prorogues Parliament for a few days, Johnson asked her to suspend it for almost five weeks.

"He is, as it were, using the rules — or some would say, bending the rules — to get what he wants," Bale said.

That alone would be unusual, but it is doubly so because it comes while the House of Commons is trying to deal with Brexit — its biggest crisis in at least a generation.

Lawmakers are set for a showdown next month as they attempt to stop the prime minister from taking Britain out of Europe without a deal, something Johnson says he will consider despite dire economic warnings from the government itself.

"It looks very unusual for you to shut down the democratic legislature during a period of political crisis," said Jack Simson Caird, a former constitutional law specialist in the House of Commons Library, which provides briefings to lawmakers.

"For one month before one of the most important moments in Britain's constitutional history, Parliament will not be sitting. That is quite extraordinary," said Caird, who is now a senior research fellow at the Bingham Centre for the Rule of Law, a research group in London.

Constitution, what constitution?

Part of the problem, as some see it, is that the U.K. does not have a "codified" constitution.

This means that rather than being contained in one document, it sprawls messily across dusty tomes and reams of legislation.

It is also very old, and leaves a lot of room for interpretation by those who wield it. The political historian Peter Hennessy calls this the "good chaps" theory: Lawmakers and bureaucrats understand the tacit rules and gentlemen's agreements that underpin British politics.

In asking the queen to suspend Parliament, Johnson is accused of ignoring those unspoken promises and using them for his own benefit.

Queen Elizabeth II welcomes newly elected leader of the Conservative Party Boris Johnson at Buckingham Palace on July 24. Victoria Jones / Pool via AP file

The "constitution relies on key players respecting precedents and traditions," said Russell at University College London. "By ignoring precedent on this matter, particularly at a time of crisis, the prime minister is arguably acting unconstitutionally."

For many, Johnson has contravened a basic constitutional rule in the U.K. that says the government should not politicize the queen.

In asking her to prorogue Parliament, he exercised something called "prerogative power" — which dates from when the monarch ruled the country and crucially cuts out the involvement of lawmakers.

"Prorogation is a good example of a part of the U.K.'s unwritten constitution that previous governments have chosen not to manipulate," according to a briefing from the Institute for Government, a think tank.

Leaders before Johnson have avoided doing this because it "would undermine trust and could be used by their opponents against them in the future," it said.