The activities of London-based Islamists came under greater scrutiny after the September 11 attacks , which brought home the vulnerability of Western countries to large-scale terror attacks . The Anti-terrorism , Crime and Security Act 2001 allowed foreign terrorist suspects to be detained indefinitely without charge . In 2004 , the Law Lords ruled that this violated European law , but it was replaced by the system of control orders in the Prevention of Terrorism Act 2005 , which provided the Government with powers to place various restrictions on suspected terrorists . The 2005 Act was subsequently replaced by the Terrorism Prevention and Investigation Measures Act 2011 . Other ones , such as Ali Salman , returned to their home countries after domestic political reforms
September 11 attacks
September 11 attacks
Londonistan