This chapter provides an overview of the UK's current response to the terrorist threat, which has evolved from the PIRA to Islamist groups. The country overhauled its legislation in 2000, just before the 9/11 attacks in the US, to address this problem. Despite that prescient legislative move, Britain has a pattern of responding to devastating and deadly terrorist attacks with new laws granting the government greater powers aimed at suppressing terrorists and their supporters. Shortly after al Qaeda struck the US, the UK amended its new legislation to give the authorities extensive new powers, including the right to detain indefinitely and without trial non-British citizens. British attitudes toward such practices have changed dramatically: what would have been rejected earlier is now widely accepted. Although these reforms undermine civil liberties, they have not threatened the country's core democratic values. Nevertheless, it is too early to say how effective they will be.