LONDON (Reuters) - Police arrested 55 people in London on Friday for a range of mostly minor offences as the force mounted one of the biggest security operations ever seen in the capital around the royal wedding.
Around 5,000 officers were on duty to control the huge flag-waving crowds, alongside around 1,000 soldiers lining the route from Westminster Abbey to Queen Elizabeth's residence, Buckingham Palace.
Specialist teams with sniffer dogs had patrolled the procession route searching for explosives, while helicopters buzzed overhead as part of the operation to protect Prince William and his new wife Kate Middleton.
The Metropolitan Police said there had been 55 arrests, with most of those detained for minor public order offences.
Police arrested 10 people at Charing Cross railway station after they were found to be carrying anti-royalist placards.
One million people lined the route between the church and Buckingham Palace and 500,000 watched the couple appear on the palace balcony after the service, police estimated.
Police said they were aware of about 10 protesters in Soho Square from the "Right Royal Orgy Group" and they were monitoring them.
A handful of protesters gathered in Trafalgar Square, where crowds were watching the proceedings on a giant screen, and displayed a banner complaining about government cuts to public services and Britain's military role overseas.
Earlier, three people -- two men aged 45 and 68 and a woman of 60 -- were detained in southeast London on suspicion of conspiracy to cause a public nuisance and breach of the peace. They were suspected of planning to behead royal effigies.
A fourth person, described by police as "a well-known anarchist," was arrested in Cambridge, northeast of London.
"A number of individuals were arrested who we felt were intent on causing disruption, committing acts of criminality or likely to cause alarm, harassment or distress to the vast majority of people who wanted to come and celebrate this joyous occasion," said Assistant Commissioner Lynne Owens.
A lawyer representing some of those held said that police had abused their power by using security concerns as a pretext to block protests that could embarrass the royal family.
"They are just not playing by the legal rules. The policing is more to do with protecting the pageantry of this occasion ... and that is not their role," said Mike Schwarz, a criminal lawyer at law firm Bindmans.
Police were prepared for a wide range of possible threats, from militant Irish republicans to Islamist groups, anarchists and stalkers.
The London force was criticised for its handling of student protests last year when demonstrators attacked a car carrying Prince Charles and his wife Camilla Duchess of Cornwall.
The huge operation to keep the crowds safe and to ensure that London's often unpredictable transport network runs well was seen as a test before the city hosts the Olympics next year.
"In many ways it is a good dry run for the Olympics," said London Mayor Boris Johnson.
Additional reporting by Olesya Dmitricova; writing by Peter Griffiths and David Milliken; editing by Keith Weir/Maria Golovnina