Afghan President Hamid Karzai was due to address students and academics at the Oxford Union debating society later today, the union said. Later in the day, the Afghan leader was expected to travel to Buckingham Palace to meet Queen Elizabeth II and Prince Charles. Karzai is due to hold talks Thursday with Prime Minister Gordon Brown on Britain's role in rebuilding Afghanistan and training its army. Karzai, who arrived in London on Sunday, is in the country for his first visit since Brown became prime minister.