High Security for Mr. Obama's Packed Diplomacy: G20, NATO, & EU

US security teams have already carried out three visits to prepare for Obama's first official visit to Britain. The first was a "site survey", the second a "pre-advance visit" which was carried out to pick sites that the president would visit. Finally there was the "advance trip", which took place last week. Its purpose was to set up equipment, sweep venues for electronic bugs, test food for poison and measure air quality for bacteria

As you all know, the President will depart from Andrews Air Force Base about 8:00 a.m. on Tuesday, traveling to London, where he'll arrive about 7:45 p.m. local time, and then spend the bulk of Wednesday and Thursday at the G20 summit.

"This is his time to make his pitch to world leaders," said Christian Weller, a senior fellow at the Centre for American Progress.

Indeed, despite all the heat and fury over this week's G20, the most important work might actually emerge from the meetings that Obama and his team have scheduled on the side, far away from the debate over the economic crisis. In effect, if the G20 were a party with a guest list, then Obama's series of mini-summits would be a VIP room; open only to a select few powerful players and conducted firmly behind closed doors.

An estimated 500 people will make up Mr Obama's entourage, 200 secret service agents, as well as policy makers, and support staff.

He will fly to Britain Tuesday morning on Air Force One, flanked by cargo planes which will hold all the transportation he needs while in Europe.

An estimated 35 vehicles will be brought to the UK for the presidential visit.

A US Air Force C-17 transporter will bring Mr Obama's armor-plated limousine, nicknamed The Beast, which is strong enough to withstand a chemical attack.   It will also carry Marine One, the VH-3D helicopter that will transfer Mr Obama from Stansted airport to the US Ambassador's residence near Regent's Park in North London.

Marine One never flies alone for security reasons and is just one among a number of decoy helicopters, designed to confuse potential terrorists.

As the plane enters UK airspace, it will be shadowed by a squadron of RAF fighter jets before landing at Stansted.

Within minutes, the Obamas will be flown by either a Blackhawk or Sea King helicopter into Central London, where they will stay at the US ambassador’s residence in Regent’s Park.

SAS troops, who have a secret base nearby, are expected to work with US Secret Service agents to ensure a ‘ring of steel’ round the Obamas.

The security operation to protect delegates attending the G20 conference is far from straightforward. The police have had to prepare for every possibility – from terrorism to riots to green custard incidents and must manage a crowd ranging from novice protesters to hardcore anarchists.

The priority is to secure the summit venue, the ExCeL centre in Docklands. The ExCeL centre has the advantage of having water on one side and it is easy to put a ring of steel around the building. This will involve police marine launches, surveillance cameras, barriers, checkpoints and cordons.

Once that is done the security focus will be on protecting the delegates' journeys in and out of the venue.