United States invasion of Afghanistan
In late 2001, the United States, supported by its close allies, invaded Afghanistan and toppled the Taliban government. The invasion's public aims were to dismantle al-Qaeda, which had executed the September 11 attacks weeks prior, and to deny it a safe base of operations in Afghanistan by removing the Taliban government from power. The United Kingdom was a key ally of the United States, offering support for military action from the start of preparations for the invasion. It followed the Afghan Civil War's 1996–2001 phase between the Taliban and the Northern Alliance groups, which resulted in the Taliban controlling 90% of the country by 2001. The invasion became the first phase of a 20-year long war in the country, and marked the beginning of the U.S. War on Terror.