Raw video of the arrival of Air Force One:
BBC: President Obama was met at Stansted Airport, north of London, by UK Chancellor of the Exchequer Alistair Darling and a senior official from the US Embassy.OBAMA'S EUROPEAN TRIP
He then boarded the presidential helicopter Marine One to make the short journey to central London where he will stay at the US ambassador's residence.
Before the start of the G20 summit of world leaders on Thursday, Mr Obama will hold extensive talks with Gordon Brown, meet the UK opposition leader David Cameron and have a private audience with the Queen.
The president is also scheduled to hold bi-lateral meetings with Russian President Dmitry Medvedev, Chinese President Hu Jintao, Indian Prime Minister Manmohan Singh, South Korean President Lee Myung-bak and King Abdullah of Saudi Arabia.
The president's wife, Michelle Obama, will take part in a series of engagements with Sarah Brown, the prime minister's wife.
Mr Brown is keen for world leaders to reach agreement on a new set of rules for regulating global finance as well as measures to boost economic demand and support poorer countries.
Tuesday: Arrives in London
Wednesday: Mr and Mrs Obama breakfast with the Browns at 10 Downing Street; Mr Obama holds talks with Gordon Brown; meets Russian and Chinese presidents, David Cameron, and the Queen
Thursday: G20 summit; Mr Obama will also meet the Indian PM, the South Korean president and King Abdullah of Saudi Arabia during the day
Friday: Departs for Strasbourg; meets French president; holds town-hall meeting; visits German Chancellor in Baden-Baden, returns to Strasbourg
Saturday: Attends Nato summit in Strasbourg; departs for Prague
Sunday: Attends EU-US summit, departs for Ankara
Monday: Departs Ankara for US
CBSNews also has a nifty map and schedule here.