The Biden administration plans to withdraw the last US troops from Afghanistan by the 20th anniversary of the 9/11 attacks later this year, ending American involvement in its longest war. President Joe Biden is expected on Wednesday to announce that he will keep thousands of forces beyond the May 1 deadline that was negotiated last year with the Taliban, but will promise to be out by September 11, according to several reports. And it was reported on Tuesday night that Britain will withdraw nearly all of its 750 troops stationed in Afghanistan after Mr Biden's announcement. British troops are heavily reliant upon US infrastructure and bases in the country. The US invaded the country shortly after the attacks on the World Trade Center buildings, marking the start of a decades-long “war on terror”. His predecessor, Donald Trump, had promised a swift drawdown but was urged by military advisers not to withdraw too quickly from the messy and intractable conflict.