A terrorist attack on British soil is “highly likely” according to the Home Secretary Theresa May, who raised the terror threat from substantial to severe.
Prime Minister David Cameron says the Islamic State militant jihadist group posed a greater threat to national security than ever before.
Military bases across the Westcountry are likely to be on alert following the announcement although an MoD spokesman for the region said the military could not comment on issues of national security.
Operational security secrecy means the MoD could not comment on what the latest terror threat means for the region’s military bases, although the warning serves to inform all those involved in the security of the nation, including the armed forced, to make sure there is an “appropriate level of security in place across the United Kindom”.
New terror warning system brought in after July 7 attacks
Mrs May stressed that there was no information to suggest an attack was imminent but said a terrorist attack was “highly likely”.
However, the terror threat was raised as Mr Cameron announced new laws to crack down on terror suspects as he warned that extremism in Iraq and Syria now poses a greater danger to Britain than al Qaida.
As the terrorist threat to the UK was raised, the Prime Minister said legislation would be introduced so it was easier to seize jihadists’ passports.
“What we are facing in Iraq now with Isil (Islamic State) is a greater threat to our security than we have seen before,” he told a press conference in Downing Street.
Mr Cameron said the intelligence and security services believed that at least 500 Britons had gone to fight in Syria and potentially Iraq.
Although he stressed that the Government had already taken steps to counter the threat of jihadists returning to commit atrocities, he said it had become clear that there was still a need to fill “gaps in our armoury”.
He will be making a statement to Parliament on Monday, giving details.
Mr Cameron said the Taliban had harboured and facilitated al Qaida terrorism, but IS was 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 added.
The gruesome murder of US journalist James Foley was “clear evidence – not that any more was needed – that this is not some far off (problem), thousands of miles away, that we can ignore”.
Earlier, Mrs May said: “The Joint Terrorism Analysis Centre (JTAC) is responsible for setting the national threat level. That informs the decisions of security professionals across the public and private sectors about the appropriate level of security in place across the United Kingdom.
“JTAC’s judgements about that threat level are made on the basis of the very latest intelligence and are independent of ministers.
“JTAC has today raised the threat level to the UK from international terrorism from SUBSTANTIAL to SEVERE. That means that a terrorist attack is highly likely, but there is no intelligence to suggest that an attack is imminent.”
Mrs May told the BBC that the UK faced a "real and serious" threat from international terrorism, urging members of the public to remain vigilant.
It is understood that there is no intelligence relating to any specific threat to the forthcoming Nato summit.
The decision comes against a backdrop of increasing concern about hundreds of aspiring British jihadis travelling to Iraq and Syria to learn terrorist “tradecraft”, and the murder of American journalist James Foley by an apparently English killer.
Sir Bernard Hogan-Howe, the UK’s most senior police officer, said Scotland Yard is prepared for an influx in case a swathe of homegrown extremists decide to return at the same time.
In a statement released today, Mrs May said: “The increase in the threat level is related to developments in Syria and Iraq where terrorist groups are planning attacks against the West. Some of those plots are likely to involve foreign fighters who have travelled there from the UK and Europe to take part in those conflicts.
“The first and most important duty of government is the protection of the British people. We have already taken steps to improve our powers and increase our capabilities for dealing with the developing terrorist threats we face. That process will continue and the British public should be in no doubt that we will take the strongest possible action to protect our national security.
“We face a real and serious threat in the UK from international terrorism. I would urge the public to remain vigilant and to report any suspicious activity to the police.”
There are five levels of threat used by the JTAC. These are:
:: Critical – an attack is expected imminently.
:: Severe – an attack is highly likely.
:: Substantial – an attack is a strong possibility.
:: Moderate – an attack is possible but not likely.
:: Low – an attack is unlikely