Britain will get its first chance to see Barack Obama this week when a White House cavalcade - complete with armoured limousines, helicopters, 200 US secret service staff and a six-doctor medical team - sweeps into the UK.

Obama will fly into London for his first visit to the UK as president of the United States on Tuesday to take part in the G20 summit in the capital's Docklands area. He will not be travelling light.

More than 500 officials and staff will accompany the president on his tour this week - along with a mass of high-tech security equipment, including the $300,000 presidential limousine, known as The Beast. Fitted with night-vision camera, reinforced steel plating, tear- gas cannon and oxygen tanks, the vehicle is the ultimate in heavy armoured transport.

In addition, a team from the White House kitchen will travel with the president to prepare his food. As one official put it: "When the president travels, the White House travels with him, right down to the car he drives, the water he drinks, the gasoline he uses, the food he eats. America is still the sole superpower and the president must have the ability to handle any crisis, anywhere, any time."

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.

Obama will start his first presidential visit to Europe when he steps down from the US presidential jet, Air Force One, at Stansted airport on Tuesday. The Boeing 747-200B is fitted with its own gym, electronic defence units and shielding to protect its complex communication devices from radiation from nuclear blasts. Among the officials on the flight will be a military officer carrying America's nuclear missile launch codes.

Obama will then be flown to central London in a VH-3D helicopter known as Marine One. Again, high-tech security will dominate his journey. Marine One is fitted with flares that can be fired to confuse heat-seeking missiles and always flies in groups containing several identical decoy helicopters.

While in town, the president will be guarded by more than 200 US secret servicemen - easily identifiable by their shirt-cuff radios and Ray-Ban sunglasses. Obama has already had some time to get used their attention. It was decided 18 months ago, when he was still a presidential candidate, that his African-American background put him at particular risk of an assassination attempt and he was provided with his security guards.

And should anything befall the President, a White House medical unit will be at hand to provide emergency care. The team consists of surgeons, nurses and other medical personnel and carries supplies of blood of the type AB, the president's blood group. At the same time, Obama will be constantly minded by his personal aide Reggie Love, who dials his BlackBerry, fetches his jacket and tie and supplies him with snacks. First Lady Michelle Obama will also have a coterie of assistants, including a secretary, a press officer and several bodyguards.

It is a striking presence and shows that, for the next few days, London, not Washington, will be the beating heart of American foreign policy. At the end of the week Obama and his massive retinue will head off for meetings in France, Germany and the Czech Republic, although not before he has indulged in an unprecedented whirlwind of diplomatic activity - he and his advisers will not just be involved in complex summit negotiations, but will also be camped out in London conducting a series of individual high-level mini-summits with the most powerful leaders in the world.

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.

The schedule is hectic and the subjects are weighty. On Wednesday, Obama will hold his first bilateral talks with President Hu Jintao of China. The meeting of America's first black president at a time of almost unprecedented economic crisis with the leader of the world's foremost rising power is historic. It comes at a time when China has been asserting its international role and taking on the US by talking of replacing the dollar as the main international currency and having a recent naval showdown with a US spy ship in the South China Sea. On the same day, Obama will also meet Russia's President Dmitry Medvedev, again in the first face-to-face talks between the two. Subjects up for discussion will include ways to co-operate to limit Iran's nuclear ambitions and debate over plans for a US missile shield that Russia views as a hostile act.

But that will be just the beginning. On Thursday, Obama will hold his first personal meeting with India's prime minister, Manmohan Singh. Their discussions will be crucial, given the fact that the explosive situation in India's neighbour, Pakistan, is the most pressing foreign policy concern of Obama's administration. Then, just to add another massively complex problem to an already exhaustive list, Obama will hold bilateral talks with the South Korean president, Lee Myung-bak. That chat comes against the backdrop of an increasingly erratic North Korea, which is threatening to attack the South and is moving to launch a long-range missile which Japan has said it might try to shoot down. "He does have a huge amount of challenges to try to tackle," said Larry Haas, a political commentator and former aide in the Clinton White House.

That is putting it mildly. But Obama is far from alone in dealing with his intense schedule. At his London "diplomatic base camp" will be an array of the best and the brightest from his new administration. Chief among them will be former rival Hillary Clinton, now secretary of state and the public face of American diplomacy. His famously combative chief of staff, Rahm Emanuel, will also be travelling to London on Air Force One. Obama's economic team includes Larry Summers, head of the National Economic Council, and Christina Romer, chairman of the Council of Economic Advisers.

The reasoning behind Obama's sudden flurry of international diplomacy is complex and only partly explained by the number of thorny problems in need of attention. In fact, Obama is cramming so much diplomacy into such a short time because so far his concerns have all been domestic. "Even when his attention has to be focused on foreign policy, his mind is still bound to be on the thing that really matters: the American economy," said Haas. Indeed Obama has been so consumed by efforts to stop and then solve America's domestic woes that the White House has barely had time to put its mind to international affairs. The London meetings offer a rare opportunity to do just that in a highly compressed time frame. "This is his time to make his pitch to world leaders," said Christian Weller, a senior fellow at the Centre for American Progress.

It also offers a brief break from dealing with domestic woes, where Obama's popularity has been slipping slightly in the face of the scandal over AIG bonuses and political splits over his huge proposed budget. Holding high-powered meetings with world leaders will allow Obama to remind Americans how much the rest of the world still admires him. It will also be good for the leaders who meet him as they play to domestic audiences. "Personally, I think every one of those leaders wants to sit down and get a photo opportunity with Obama," said Dan Mitchell, a senior fellow at the Cato Institute. "The mere fact that he is the new president has still got something special about it abroad."

The entourage

Apart from the 200 secret service personnel who will follow Obama on his European tour, the president's entourage will also include representatives of the White House Military Office, the White House Transportation Agency, the White House Medical Unit, the Marine Corps Helicopter Squadron, the State Department Presidential Travel Support Service, the US Information Agency, the Immigration and Naturalisation Service and the Customs Service.

In addition, there will be staff from the White House kitchen ready to turn out a quick burger should the president suddenly feel peckish.

Michelle Obama will have eight of her own staff, including a secretary, a press officer and bodyguards. And Obama's personal aide Reggie Love - called by the president "the kid brother I never had" - will be at hand to provide pens, Nicorette gum, throat lozenges, tea or even aspirins.

The Beast

With its armour-plated body and doors, a raised roof, and reinforced steel and aluminium, The Beast will be Obama's official car. It boasts a titanium and ceramic superstructure and a sealed interior forming a "panic room" capable of shielding him from even a chemical weapons attack. Equipped with a night-vision camera and an armoured petrol tank filled with foam to prevent explosion should it suffer a direct hit, it also has pump-action shotguns, tear-gas cannon, oxygen tanks and bottles of the president's blood. Its tyres allow it to keep driving even if they have been punctured.

Marine One

Obama will be ferried from Stansted to the US ambassador's residence in Regent's Park, London, in a VH-3D helicopter. For security reasons, helicopters are now preferred to motorcades, which are also dearer and more difficult to organise. Much of the current fleet of 19 presidential helicopters was built in the 1970s and after 11 September 2001, when it was decided faster and safer helicopters were needed. But last month Obama said his current presidential helicopter was "perfectly adequate", a clear sign he is ready to cancel a multibillion-pound contract to replace it.

Air Force One

Using the most famous air traffic control call sign of any US aircraft, Air Force One, the president will arrive in his customised Boeing 747-200B series aircraft.

Beyond its armoured glass in all windows, Obama will have dined in the presidential suite and could even have worked out in his personal gym and taken a shower.

The aircraft has been designed with security as its priority and is equipped with armour-plated wings capable of withstanding a nuclear blast from the ground, flares to confuse enemy missiles and electric defence systems able to jam enemy radar. Mirror-ball technology in the wings is able to scramble infra-red guidance systems. More than 200 miles of wiring are specially shielded from electromagnetic interference caused by a nuclear attack.

Should the president feel the need to retaliate offensively, Obama is able to launch a nuclear strike while flying. The aircraft, among the most photographed in the world, has 85 telephones, 19 televisions, computer suites and faxes to ensure Obama stays in touch with the outside world. At the rear of the aircraft is Obama's travelling press corps.

Secret Service

More than 200 Secret Service staff will protect the president during the trip, instantly recognisable by their dark business suits, sunglasses and communication earpieces.

John F Kennedy, Ronald Reagan and George W Bush were attacked while appearing in public. Kennedy was killed and Reagan seriously injured, while Bush survived when a hand grenade thrown towards his podium failed to detonate.

Secret Service personnel have made three missions to the UK during which they have swept venues for bugging devices, tested food for contamination and measured air quality for bacteria. Obama was offered bodyguards over a year ago following concern that his African-American roots made him a target.

• The following correction was printed in the Observer's For the record column, Sunday 5 April 2009. Above we said representatives of "the Immigration and Naturalisation Service" (INS) and "the US Information Agency" (USIA) would accompany President Obama on his European tour. The USIA was closed in October 1999 when its information functions were incorporated into the State Department and its broadcasting services consolidated into the Broadcasting Board of Governors. The INS ceased to exist in March 2003 with most of its functions transferring to the Department of Homeland Security.