The protester had only got a few bars into his version of the Beatles' Yellow Submarine, recast as "we all live in a fascist regime", when the plain clothes officers moved in.

Inside Westminster Abbey, Prince William and Catherine Middleton were exchanging vows watched by millions, but in nearby Soho Square, the expression of different views by a few people met a robust and, according to some present, disproportionate response.

About a dozen policemen grabbed the singer, sparking a clash with his colleagues, changing the mood of a small and peaceful gathering as he was handcuffed and bundled away. "He had articles on him to cause criminal damage," explained Chief Inspector John Dale, to loud protests.

"You just incited a peaceful situation into violence," shouted a bystander.

"The police should be peaceful and respect our right to protest," said another witness, Jed, 19.

The action against the 10 or so people participating in the Right Royal Orgy in Soho Square was one of several pre-emptive strikes by Scotland Yard. Police said they made a total of 52 arrests including 13 at Charing Cross station, where people were found to have climbing equipment and anti-monarchy placards, in addition to 21 arrests during raids of five squats in London on Thursday morning.

Trouble flared at an unofficial street party in Glasgow organised through social networking websites. Strathclyde police said they made 21 arrests in Kelvingrove Park, for a variety of offences mostly related to disorderly behaviour and drunkenness.

A spokeswoman for the force said: "Police were aware of this unplanned, unauthorised event and put in place contingencies to ensure an appropriate and proportionate policing response."

Chief Superintendent Bernard Higgins, from Strathclyde police, said: "It's really disappointing that on the day of the royal wedding we witnessed the scenes we did. At one point my officers came under attack and one was taken to hospital suffering from a head injury. He has been discharged and will make a full recovery.

"We made a number of arrests at the time and we will now study CCTV footage and make further arrests if appropriate. The level of drunkenness was completely unacceptable and frankly irresponsible."

Four people were arrested the night before the wedding, three in London and one in Cambridgeshire, for conspiracy to cause a public nuisance and breach of the peace. One of them, Chris Knight, was planning to behead an effigy of Prince Andrew with a theatrical guillotine, in what his friends said was a piece of street theatre.

By the time the marriage vows had been made, the police had imposed a section 60 blanket stop-and-search order around the whole royal wedding zone, after a few individuals were seen putting scarves over their faces in Soho Square.

The move allowed officers to search people without discretion. It can be issued when police believe, with good reason, that there is the possibility of serious violence or that a person is carrying an offensive weapon. It was imposed along with a section 60a order, which allows officers to remove headgear and masks from demonstrators.

The powers remained in place for several hours, although the police said the mood in both Soho Square and at the Republican Tea Party in Red Lion Square, Holborn, was calm.

Officers also swooped on five people, three of whom were wearing zombie make-up, when they entered a branch of Starbucks on Oxford Street. They were arrested "on suspicion of planning a breach of the peace".

They were all handcuffed and held in a police van and gave their names as Amy Cutler, 25, Rachel Young, 27, Eric Schultz, 43, Hannah Eisenman-Renyard, and Deborah, 19, an anthropology student at the University of East London.

"We've been pre-emptively arrested under suspicion of planning a breach of the peace," Cutler told the Guardian from the police van. "We went to Starbucks to get a coffee and the police followed us in."

"We were just dressing up as zombies," said Amy, who was wearing a "marry me instead" T-shirt. "It is nice to dress up as zombies."

The decision to arrest people on Thursday in advance of them carrying out any protest drew an angry response from their friends and relatives. In Cambridgeshire officers arrested Charlie Veitch, an anarchist, for conspiracy to cause a public nuisance and breach of the peace. His girlfriend, Silkie Carlo, said Veitch had been planning to use a megaphone to make "ironic comments" in Soho Square. "I'm outraged. It's easy to hide all this behind the beauty and the spectacle and the tiaras of the wedding, but when people with opposing political ideas are being rounded up to keep them away from public view it doesn't make us any different from China," she said.

In London the daughter of Chris Knight, who was arrested with his partner and a friend, said the police were quashing freedom of expression. Olivia Knight said: "My father was going to take part in a performance. It was going to be in the great British tradition and was going to be playful, peaceful and satirical to highlight the obscenity of the royal wedding and the grotesque nature of the taxpayer having to pay for the Windsor wedding at a time of such austerity."

The Metropolitan police brushed off any criticism. Assistant Commissioner Lynne Owens, in overall charge of the policing operation, said it had been "an amazing success". It justified the police's preemptive action in the days and hours before the wedding and the decision to throw a Section 60 Stop and Search Order around the whole wedding zone.The Yard said the police action had allowed the demonstrations in Soho Square and Holborn to go on freely.