Green Party leader Zack Polanski says that he "feels sorry for the King" for being sent to meet President Donald Trump in the US – and blames Sir Keir Starmer for putting him in that position.
It comes as security concerns intensify following what the White House termed an attempted assassination of the president at the White House Correspondents Dinner in Washington.
The incident has reignited debate over whether the King and Queen should travel to the United States.
Speaking in Newcastle, Mr Polanski said: “I actually feel really sorry for the King, that he’s been paraded around as some sort of privilege for Donald Trump.
“It’s important to put things in perspective, just a couple of weeks ago, Donald Trump posted on Truth Social, his social media platform, ‘An entire civilisation could be wiped out this evening, it doesn’t have to happen, but it probably could’.
“That’s not a man we should consider our ally or in a special relationship with.
“That’s a man we should be sanctioning and making sure that we’re condemning.
“And the fact this kind of awful parade of King Charles having to go there, why is Keir Starmer so obsequious to Donald Trump?
“Of course we should have a diplomatic relationship with the president, of course, we should talk to him on a whole range of things.
“But sending King Charles over there to meet him, as if he’s some sort of friend, or some sort of ally, will be difficult for a lot of British people to watch, and they’ll wonder why Keir Starmer, as with so many decisions, has made that decision.”
Buckingham Palace announced on Sunday that Charles’s visit to Washington would still go ahead largely as planned. However, it is understood there will be some modest operational adjustments to one or two royal engagements.
The historic visit, the King’s first visit to the US as monarch, will mark the 250th anniversary of American independence and herald the start of celebrations across the US.
The royal couple, who will begin their visit with a private tea hosted by the president and first lady, will also commemorate the 25th anniversary of the September 11 terrorist attacks that brought down New York’s Twin Towers.
Mr Polanski said he personally has “no time” for the monarchy.
“We live in the wealthiest country in the world,” he said.
“You have rich people are getting richer than they’ve ever been before, while people are struggling and nurses are queueing up at food banks.
“I don’t think it’s a good symbol.”
Local elections mapped: Where Labour is facing a ‘calamity’ and key seats to watch
Trump’s blindness to Iran and Russia’s military collaboration is staggering
Who is Morgan McSweeney? Starmer’s right-hand man and Peter Mandelson ally
Prime Minister Mark Carney announces creation of Canadian sovereign wealth fund
PM to face vote which could spark probe into whether he misled MPs over Mandelson
Reform UK bus and taxi the only vehicles at Jenrick’s ‘national fuel protest’