[JURIST] The UK’s Joint Terrorism Analysis Centre (JTAC) [official website] on Friday changed the threat level for terrorist attacks against the UK [press release] from “substantial” to “severe,” indicating that a terrorist attack against the UK is highly likely, although there is no evidence to suggest an attack is imminent. In addition to the change in threat level, the office of UK Prime Minister David Cameron [official website] announced the implementation of new policies and proposed legislation to disrupt terrorist activity [press release] and prevent extremism in the UK, including measures to facilitate the revocation of passports from potential terrorists traveling to and from conflict areas such as Syria and Iraq. Chief Constable of the Metropolitan Police Sir Bernard Hogan-Howe [official profile] has said that up to 600 UK citizens have left the UK to join Islamic State (IS) [BBC backgrounder; JURIST news archive].

The change in threat level and Cameron’s proposed legislation comes in response to intelligence suggesting that the recent IS execution of US journalist James Foley was conducted by a citizen of the UK [Huffington Post report]. Human Rights Watch (HRW) and Amnesty International (AI) [advocacy websites] released separate statements earlier this month condemning Foley’s execution as a war crime. Foley was a freelance journalist conducting war correspondence on the situation in Syria when he was abducted by IS [CNN report] in November 2012. IS released a video on Tuesday depicting Foley’s beheading [Newsweek report] by a masked IS agent, now thought to be a UK citizen.