G20 summit: 20 fascinating facts

Although it's known as the G20, Gordon Brown has invited delegates from countries outside the elite club, including the Netherlands and Spain.

Barack Obama will be staying at Winfield House, the official residence of the US ambassador, which was built in the 1930s with money inherited from Franklin Winfield Woolworth who made his fortune founding the now defunct retail chain.

Carla Bruni, the wife of President Nicholas Sarkozy of France, will not accompany her husband on the trip. But she will entertain Michelle Obama at a separate event in Strasbourg on Saturday.

The Queen and the Duke Of Edinburgh are hosting a reception at Buckingham Palace on Wednesday evening, ahead of the No 10 dinner. Every country attending the G20 is allowed to send up to five people.

The US president will be flown from Stansted to London in the helicopter Marine One. But he is also bringing across a number of decoy helicopters, to confuse potential terrorists.

Police are expecting around 10,000 people to take to the streets in the City on April 1. A countryside march in 2002 attracted 400,000 protesters.

G20 Meltdown, the group co-ordinating the four processions that will converge on the Bank of England, has set up its own Twitter account to keep activists informed.

Before the Government decided on the ExCeL centre in London's Docklands as the venue for the summit, Watford in Hertfordshire was shortlisted as a possible location. Sites in Birmingham and Manchester were also touted.

The gift bag to be handed out to delegates at the summit will include a designer tea towel created by Northern Ireland-based firm Thomas Fergusons Irish Linen.

The Foreign Office has said that the summit is likely to cost the Government around £20 million. But this is dwarfed by the 2008 G8 summit in Japan, which reportedly cost $285 million to stage.

The last time so many world leaders gathered in Britain was in 1946, for the first general assembly on the United Nations.

After months of preparations, all the business of the summit will be carried out in four-and-a-half hours of formal talks and three working meals.

The G20 was only established in 1999 to deal with the financial crises of the late 1990s. Its first meeting was in Berlin, Germany.

Britain is the ninth country to chair the G20, after Canada (1999-2001), India (2002), Mexico (2003), Germany (2004), China (2005), Australia (2006), South Africa (2007) and Brazil (2008).

Jamie Oliver is cooking dinner for the world leaders at No 10 on Wednesday night – but their spouses will be served in a separate room at Downing Street to give the politicians space to talk.

The Queen is holding private audiences with several statesmen during the summit – including the leaders of Australia and Canada and President Obama.

Documents leaked before the summit have suggested that Canada, Australia, Russia, Argentina, Indonesia, Mexico and Turkey are on a list of less important "B team" nations. Countries on the "A list" compiled by Britain are Brazil, China, France, Germany, India, Italy, Japan, Saudi Arabia, South Africa, South Korea, and the United States.

The G20 economies account for over 80 per cent of the global gross national product (GDP), about 80 per cent of world trade and some two thirds of the world population.

The police operation at the summit is code-named Operation Glencoe. Some 84,000 police man hours have been allocated to the event.

The security work in London on April 1 is complicated by another event taking place in the capital that evening – England are playing Ukraine at Wembley in a World Cup qualifier.