Police cannot rule out pre-emptive strikes against anarchists plotting to disrupt the royal wedding, Scotland Yard has said.
In one of the biggest security operations in the history of the Metropolitan police, just under 5,000 police officers - including armed and undercover teams - will be on duty on 29 April in the city of Westminster and around the centre of London.
So far, two groups have indicated that they wish to protest: Muslims against Crusades, who asked to demonstrate outside Westminster Abbey but were refused permission, and the English Defence League. The EDL indicated it would mount a demonstration if Muslims against Crusades did so.
Sixty individuals who have been arrested at past demonstrations, such as the TUC anti-cuts protest and the student demonstration against the introduction of fees, have been banned from the city of Westminster as part of their bail conditions. Action will be taken against them if they enter the city on the day.
In addition, the Met is working with forces across the country and is using "spotters" to identify those within the so-called "black bloc" of anarchists intent on causing trouble.