A military band serenaded the President and Mrs. Bush moments after Air force One touched down Wednesday night at a military base outside Londeon. Mr. Bush headed for the home of the US Ambassador to Britain for some sleep before a long day of ceremony and substance. There will be a luncheon meeting with Queen Elizabeth and a bit of sightseeing in London, before Mr. Bush leaves the confines of the city to meet with Tony Blair. A spokesman for the prime Minister says their discussions will touch on two issues that have divided America and its European allies: Mr. Bush's rejection of the Kyoto agreement on global warming and his plan to develop a missile defense system. These are issues that are also expected to come to the fore later in the week when President Bush takes part in a summit of the world's leading industrialized nations, plus Russia. The item at the top of the official agenda for the meeting in Genoa, ltaly is the search for ways to help promote development in the world's poorest countries.