British ministers and police provoked anger and dismay as they signalled tough new security measures aimed at public rallies after the violence that marred the Trades Union Congress anti-cuts protests.
Theresa May, the Home Secretary, was warned against a kneejerk reaction to the trouble amid fears that moves to ban known hooligans from demonstrations could be abused by over-zealous officers.
The Metropolitan Police are also planning the widespread use of stop-and-search powers against extremists attempting to disrupt the royal wedding on April 29.
May spelt out the plans in an emergency Commons statement into Sunday's events, when the TUC's peaceful protest was hijacked by gangs of anarchists and anti-capitalists.
A mob broke away from the up to 500,000 demonstrators on the main march, smashing windows in Oxford St, daubing graffiti on banks and staging a sit-in at the high-end food store Fortnum & Mason.
Scotland Yard plans to increase the use of stop-and-search powers on the day of the royal wedding, the next major test of policing methods in the capital, as well as stationing more officers at rail and Tube stations to spot possible troublemakers.
Boris Johnson, the London mayor, vowed there would be no repeat of last weekend's trouble when Prince William and Kate Middleton marry.
He said: "It will not be tolerated and it would be extremely unwise of anyone to try to spoil a happy day of national celebration."
May backed the use of soccer-style banning orders against people suspected of planning to use legitimate protests as a pretext for violent action.
They would be barred from travelling to demonstrations and could be arrested if they refused to comply.
The Home Secretary told MPs: "Just as the police review their operational tactics, so the Home Office will review the powers available to the police. I have asked the police whether they need further powers to prevent violence before it occurs.
"I am willing to consider powers which would ban known hooligans from rallies and marches and I will look into the powers the police already have to force the removal of face-coverings and balaclavas."
Scotland Yard has received five complaints about police conduct during Sunday's protests, including one allegation of assault.
Of the 201 people arrested, 138 have been charged with aggravated trespass - all of them for taking part in the Fortnums protest. In total there are 149 charges, including one of violent disorder against Omar Ibrahim, 31, from Glasgow, accused of throwing a smokebomb into Topshop's flagship store on Oxford St.
Tim Matthews, a spokesman for UK Uncut, which organised the sit-in at Fortnum & Mason, said: "This was not a protest by people wearing balaclavas and breaking things. It was a peaceful, mild-mannered gathering by people from all walks of life - teachers, hospital workers, charity workers. People who took part now find themselves charged with a criminal offence simply for exercising their right to protest."
Tom Brake MP, co-chairman of a Liberal Democrat parliamentary policy committee, said: "We must not have a kneejerk reaction to what happened."