Home Secretary Theresa May said the decision to raise the threat level was related to developments in Iraq and Syria, but that there was no information to suggest an attack was imminent. Some of the plots are likely to involve fighters who have traveled from Britain and Europe to take part in fighting in the Middle East.
“We face a real and serious threat in the U.K. from international terrorism,” she said. “I would urge the public to remain vigilant and to report any suspicious activity to the police.”
May says the decision by the Joint Terrorism Analysis Center is made on the basis of intelligence and is independent of government. “Severe” is the second-highest of five levels.
British police have appealed to the public to help identify aspiring terrorists after the murder of an American journalist focused attention on extremism in the U.K.
The involvement of a person of British nationality in James Foley’s murder underscored the need to identify those who might travel abroad to fight or are at risk of being radicalized.
Also on Friday, Prime Minister David Cameron said he'll introduce new laws to combat terror suspects, pledging to seize passports to fight what he described as an extremist threat more dangerous than any previously seen.
Cameron's remarks came just after authorities on Friday raised the terror threat level to severe, the second highest level. The decision was related to developments in Iraq and Syria, but there was no information to suggest an attack was imminent.
Cameron told reporters that while the Taliban facilitated al-Qaida terrorism, the Islamic State group is "effectively a state run by terrorists."
"We could be facing a terrorist state on the shores of the Mediterranean and bordering a NATO member," he said.