Some wore T-shirts blazoned with the words "Off with their Heads." Others favored phrases such as "Citizens not Subjects" or "England doesn't need a Queen."
Amid the huge outpouring of royalist support and fervor around Britain as a potential future king of England and his bride exchanged wedding vows Friday was the smaller voice of naysayers far less impressed by the idea of celebrating kings, queens, dukes and duchesses.
In London, in a corner of central Red Lion Square a short distance from, but out of sight and sound of, the cheering crowds around Westminster Abbey and Buckingham Palace, the group called Republic held the main anti-monarchy street celebration: Not the Royal Wedding.
"To Wills and Kate. While we wish you every happiness in married life, we oppose your right to inherit public office and will do all we can to ensure that the Queen's successor is chosen by the British people," read a document on display.
"It's an enormous waste of public money," Rachel Schwartz Holford, a Londoner, said of the royal wedding. "It's coming out of our tax money for people who haven't been elected."
About 2,000 people attended the event at Red Lion Square during the course of the day, according to police. Event organizer Tim Sharp said: "We've seen our membership shoot up recently. We think we represent about 20% of the country."
As thousands of local street parties celebrated the happy couple up and down the country, anti-royalists with strong sentiments hosted various events of their own, though far fewer. Earlier this week, wedding fever in southeastern England waned noticeably toward indifference in the north, with small pockets of hostility in some places.
In London, police arrested about 55 people suspected of planning a disruptive anarchist protest, the Daily Telegraph reported.
In Edinburgh, where the wedding was beamed to a large crowd in the city center, a brief clash was reported.
Glasgow stood out for its initial lack of royal interest with few street party requests, but Scottish TV reported Friday that almost 5,000 people turned up for an impromptu celebration in the city's Kelvingrove Park and the BBC reported 15 planned parties.
At the London event, people generally were not hostile toward the young couple who had just wed.
"They're beautiful, young and in love. I'm not surprised that many people got caught up in the occasion today," said Carolyn Pawley of Leicester.
John Schwartz Holford, husband of Rachel, said any change to the British system of royalty would come "not in our lifetime." He also said he had a soft spot for William.
"I think he's a man of the people. I'm sure he'd rather be somewhere else, doing something else."
Stobart is a staff writer in The Times' London bureau.