Less than six months into his reign, King Charles is at the center of a Brexity political storm.

The U.K. monarch’s meeting Monday with European Commission President Ursula von der Leyen — on the day a long-awaited deal to put months of wrangling over post-Brexit trade was struck — sparked swift fury among Euroskeptic politicians, who saw it as a crude attempt to bump them into backing an agreement.

“I cannot quite believe that No10 would ask HM the King to become involved in the finalising of a deal as controversial as this one,” tweeted Northern Ireland’s former First Minister Arlene Foster. The “crass” move would, she said, “go down very badly” in Northern Ireland.

The U.K. sovereign is, according to the unwritten British constitution, meant to represent the whole country and steer well clear of politics (although as prince of Wales, Charles was seen to have sailed close to the wind).

Both No. 10 Downing Street and the European Commission stressed that von der Leyen’s visit was separate from talks on the Northern Ireland protocol. The BBC and the Daily Mail both reported that the pair, who have met before, would discuss climate change and the war in Ukraine. A European Commission spokesperson said von der Leyen’s meeting with the king was “not part” of the Brexit protocol talks, and instead on “separate tracks of discussion.”

But the move came on a day of highly-choreographed political theater, including a joint press conference between Prime Minister Rishi Sunak and von der Leyen in Windsor, home to royal residence Windsor Palace. Brexiteers were quick to make what they saw as a link, and trained their fire on No. 10.

“I think the sovereign should only be involved when things have been completed and accepted,” Jacob Rees-Mogg, a former Cabinet minister, told broadcaster GB News on Monday morning.

He added: “The king gives assent to acts of parliament when parliament has agreed; he doesn’t express his view on acts of parliament when they are going through the process. I think the same applies, that his majesty should not be involved until there is full support for this agreement.”

Nigel Farage, the former Brexit Party leader and ex-MEP, said it was “absolutely disgraceful” to “even ask the king to get involved in something that is overtly political in every way.”

Before an official announcement came, Democratic Unionist Party MP Sammy Wilson branded the idea — first reported by Sky News on Friday evening — a “cynical use, or abuse of the king” that would only raise the temperature in Northern Ireland.

Conflicting accounts about the genesis of the meeting were flying on Monday as the face-to-face was confirmed.

A palace spokesman said the king was “pleased to meet any world leader if they are visiting Britain,” and stressed it is “the government’s advice that he should do so.”

Downing Street pointed to the palace. Sunak’s official spokesman said Monday that meeting von der Leyen was “fundamentally” a decision for Buckingham Palace, but declined to say who had requested the sit-down.

The prime minister “firmly believes it’s for the king to make those decisions,” the spokesman told reporters at the daily No. 10 press briefing.

“It’s not uncommon for his majesty to accept invitations to meet certain leaders,” he added, pointing to Charles’ recent audiences with the presidents of Poland and Ukraine.

Former Cabinet minister — and close ally of ex-Prime Minister Boris Johnson — Nadine Dorries wasn’t buying it. “Either No10 is lying or Buckingham Palace,” she tweeted. “I know which one my money is on.”