London calling for supreme security

The biggest security operation in British history will move into top gear today as world leaders gather for the G20 summit.

A police officer monitors CCTV screens showing prominent areas in London.

London // The biggest and most complex security operation in British history will move into top gear today as world leaders gather in London for the G20 summit. All police leave has been cancelled and more than 10,000 officers, many brought in from other UK forces, will be on duty around the clock in a bid to prevent London from being turned into a battleground over the next two days.

For the first time, squads equipped with Taser guns will be on call to try to keep a string of supposedly peaceful demonstrations in various parts of the capital from getting out of hand. "There are three basic problems," a police source said yesterday. "There are the demonstrations planned simultaneously for various parts of the city; there is the obvious threat of terrorism when you have 19 heads of state in town, and there is the problem of the lone nutcase who might want to do anything from throwing an egg at his least favourite president, to shooting him or her.

"Any one of these situations is a problem in itself. When you have all three coming together at the same time, it poses some tough logistical dilemmas." Today, which is All Fools' Day in the United Kingdom, there are at least five demonstrations planned. One, the Financial Fools' Day protest, involves four marches converging on the Bank of England in the City of London, the financial district. By yesterday, many financial institutions had boarded up entrances and windows in a bid to prevent damage.

There is also the Fossil Fools' Day protest, during which environmental campaigners plan to demonstrate at the ExCel Centre in east London's docklands, owned by the Abu Dhabi National Exhibitions Co and the venue of tomorrow's G20 summit. The organisers are also setting up a protest camp outside the European Climate Centre in central London. Another flashpoint could be an anti-war march starting at the US Embassy and organised by such groups as the Stop the War Coalition, the Palestine Solidarity Campaign and the British Muslim Initiative.

Additionally, there are likely to be protests at the University of East London and at a meeting this evening of oil company chiefs at the British Museum. "On Saturday, we had a march through London of about 35,000 people and it all went off peacefully," the police source said. "That, though, was quite a middle-class event with people protesting about everything from world hunger to the plan to build a third runway at Heathrow.

"The events of Wednesday and Thursday are of a very different nature and risk being hijacked by anarchists who just want to stir up trouble and violence for the sake of it." Tomorrow, the focus of the police operation, codenamed Glencoe, will turn to the summit itself, though marches on the ExCel Centre, which will be ringed with officers and anti-bomb barriers on three sides and by surface and underwater patrols on its river side, are unlikely to get within shouting distance of the world leaders.

Instead, protesters plan to give the delegates an early morning call with noisy demonstrations outside the hotels and embassies they are staying in, as well as holding various marches. "The police have had to prepare for every possibility - from terrorism to riots to custard-throwing incidents - and must manage a crowd ranging from novice protesters to hardcore anarchists," Andy Hayman, the former Metropolitan Police assistant commissioner in charge of special operations, wrote in The Times yesterday.

"What makes the demonstrations unique is the range of pressure groups planning to protest. Disorder has to be nipped in the bud, otherwise it can escalate at frightening speed, putting the police on the back foot. If required, snatch squads will be used to remove troublemakers. "With the [G20] venue secure, protesters are likely to demonstrate elsewhere. Creating a cat-and-mouse chase across London. Text messaging could help change a protest location at the last minute. Despite months of preparation, things will be tense."

With many of the protests focusing on London's financial centre, banks are urging their employees to "dress down" over the next two days so that they are not so easily recognisable. They have also been told not to engage demonstrators in arguments. One man, of course, will be protected like no other: the US president, Barack Obama, who flew into Stansted airport in Essex yesterday, bringing with him about 200 armed agents.

He is staying at the US ambassador's residence in Regent's Park and will travel everywhere by helicopter, except for his trip to Buckingham Palace this afternoon for a private audience with the Queen before a reception there for all the G20 heads. It means that the British public are unlikely to see much of the US president except on their TV screens. Not so for prime minister Gordon Brown, who plans to speak to some of the protesters outside St Paul's Cathedral today.

"I think most people who are making their views known are wanting to do so in a peaceful way," he told GMTV yesterday "After all, people are talking about jobs, about protecting the environment and helping the poorest countries." But he added: "No violence can be tolerated, no intimidation of people is allowed and the police will act very quickly if there is any threat to property or people." Yesterday, detectives were continuing to question three men and a woman detained in Devon. They were arrested under anti-terrorist legislation after the discovery of imitation firearms, makeshift explosive devices and "political literature" at a house in Plymouth. Police have refused to say if the arrests were connected to the summit.