[LONDON] Queen Elizabeth II was left exposed Tuesday to suggestions that Boris Johnson used her as a political pawn by having her approve a suspension of parliament that the Supreme Court has unanimously ruled broke the law.
Constitutional experts say the 93-year-old head of state had no choice but to give royal assent to Mr Johnson's request to slash the number of days parliament meets before Britain is due to leave the European Union on October 31.
Britain has functioned for centuries as a constitutional monarchy in which the sovereign can only act on the prime minister's advice.
In other words: the monarch has authority in name only while her prime minister wields the political power that counts.
"It's the oldest rule in the constitution," Durham University constitutional expert Robert Craig said.
Yet the five-week suspension she signed off on looked suspiciously long from the start. The court noted Tuesday that most prorogations last for a matter of just days.
These are required when parliament's session draws to an end and the prime minister prepares to set out the agenda for the year ahead.
And the one Mr Johnson had asked for came in the politically-explosive run-up to Britain's scheduled withdrawal from the European Union on October 31.
"This is a hideous moment for the palace," BBC royal correspondent Jonny Dymond wrote.
It also raises even bigger questions as Brexit day nears and the debate over the monarch's role in UK politics rumbles on.
"For decades, for centuries, (Britain's constitutional monarchy) has been governed by convention and precedent, and an unspoken agreement not to push things too far," Mr Dymond said.
"Boris Johnson blew that apart."
University of Liverpool law professor Mike Gordon speculated before the ruling that Mr Johnson's "government might advise the queen not to give the royal assent" to the parliamentary law ruling out the possibility of Britain's crash exit from the EU.
"And at that point we'll be in difficult constitutional territory," said Mr Gordon.
"The convention she gives the royal assent to anything parliament will pass clashes with the convention she acts on ministerial advice."
The last monarch to refuse royal assent - signing a bill into law - was queen Anne in 1708.
But much of what has been happening in UK politics has not been recorded in history for centuries.
It is hard to imagine anyone better-versed in the sovereign's duties than Britain's longest-serving monarch - on the throne since 1952 and holding a special place in most Britons' hearts.
The sovereign is usually only approached by ministers when their attempts to sort out the various political debates among themselves all fail.
The closest this queen has come to being drawn into politics was during the 1975 constitutional crisis in Australia.
Her governor-general John Kerr had sacked Australian prime minister Gough Whitlam and the queen refused to get involved in the political furore that followed.
Former British prime minister John Major said he hoped the queen is spared any more possible blushes by Mr Johnson.
"No prime minister must ever treat the monarch or parliament in this way again," Mr Major said.