The United States declared a War on Terror following the attacks . British forces participated in NATO 's war in Afghanistan . Blair took the lead ( against the opposition of France , Canada , Germany , China , and Russia ) in advocating the invasion of Iraq in 2003 . Again Britain was second only to the US in sending forces to Iraq . Both sides wound down after 2009 , and withdrew their last troops in 2011 . President Bush and Prime Minister Blair provided sustained mutual political and diplomatic support and won votes in Congress and parliament against their critics at home . During this period Secretary of State Donald Rumsfeld said that " America has no finer ally than the United Kingdom . " The 7 July 2005 London bombings emphasised the difference in the nature of the terrorist threat to both nations . The United States concentrated primarily on global enemies , like the al-Qaeda network and other Islamic extremists from the Middle East . The London bombings were carried out by homegrown extremist Muslims , and it emphasised the United Kingdom 's threat from the radicalisation of its own people
7 July 2005 London bombings
7 July 2005 London bombings
United Kingdom–United States relations