World leaders are expected to begin to arrive.
President Obama is expected to fly into Stansted airport in Airforce One before being transferred by helicopter to the American ambassador's residence in Regents Park.
Chef Jamie Oliver will be preparing the meal on Wednesday evening
There will be bilateral meetings between some of the leaders. For example, President Obama is expected to have his first face-to-face meetings with President Hu Jintao of China and President Dmitry Medvedev of Russia.
During the day there are likely to be protests and demonstration in central London and around the ExCel exhibition centre in Docklands.
In the afternoon the Queen will host audiences with the Prime Ministers of Australia and Canada. She will meet the US President and the First Lady later in her private apartment.
At 6pm Her Majesty The Queen and HRH Prince Philip will host a reception for delegates at Buckingham Palace.
Afterwards at 8.30pm the Prime Minister will host dinner for the Heads of Delegation at 10 Downing Street. The spouses go for separate dinner in Number 10 while the finance ministers and central bankers have dinner at Tate Britain
On Thursday the attention shifts to the Summit itself at the ExCel Centre in London's docklands. The leaders will begin to gather there from 7am.
A series of plenary sessions will culminate in a press conference in the afternoon.
The Foreign and Commonwealth Office