A student arrested on suspicion of pelting the King and Queen Consort with eggs said the crowd around him reacted with “pure rage”.
The royal couple had just arrived in the city to unveil a statue in honour of the late Queen at York Minster when a figure in the crowd threw four eggs, all of which missed.
The man was heard to shout “this country was built on the blood of slaves” as he was detained by police.
People in the crowd booed him and shouted, “God save the King”.
North Yorkshire Police said a 23-year-old arrested on suspicion of a public order offence had been interviewed and has now been bailed.
Mr Thelwell told The Mirror: “After I was arrested the experience of that crowd, literally screaming and wailing with pure rage.
“Saying that my head should be on a spike, that I should be murdered on the spot.
“It doesn’t phase me because I understand what fascism is, what it looks like.
“People were ripping chunks of my hair out, they were spitting at me.
“People lost their minds.”
He said his bail conditions included not going within 500m of the King and not possessing eggs in a public place, which he claimed to have had amended so he could do his groceries.
He did not believe in kings and said everyone should be treated equally and his protest was about the state of the country and its “descent into fascism”.
Mr Thelwell told the newspaper he has received death threats.
The University of York later said it was “appalled” by the images and will consider misconduct proceedings.
The best videos delivered daily
Watch the stories that matter, right from your inbox