In a televised statement from Downing Street, UK PM Theresa May said Britain has increased its security threat level to the highest possible "critical" from "severe", following Monday's suicide attack in Manchester that killed 22 people, including children, and she also said members of the army would be deployed to "assist police" and boost security at key sites, and that military personnel would be deployed at public events such as concerts and sports events.
“Members of the armed forces deployed in this way will be under the command of police officers,” May said, adding that "we cannot ignore that there is a wider group of individuals linked to Manchester attack".
"It is now concluded on the basis of today's investigations that the threat level should be increased for the time being from severe to critical," she said in a televised statement following a meeting of the government's crisis response committee.
"This means that their assessment is not only that an attack remains highly likely but that a further attack may be imminent."
May continued: "I do not want the public to feel unduly alarmed. "We have faced a serious terror threat in our country for many years and the operational response I have just outlined is a proportionate and sensible response to the threat that our security experts judge we face.
"I ask everybody to be vigilant and to co-operate with and support the police as they go about their important work.
"I want to end by repeating the important message I gave in my statement earlier today.
"We will take every measure available to us and provide every additional resource we can to the police and the security services as they work to protect the public.
"And while we mourn the victims of last night's appalling attack, we stand defiant.
"The spirit of Manchester and the spirit of Britain is far mightier than the sick plots of depraved terrorists, that is why the terrorists will never win and we will prevail."
* * *
Britain’s threat level has been at the “severe” level since 2014. It has only been at a “critical” level twice before, in 2006 and 2007 (see table below). May said the independent body which sets the threat level had recommended it be raised after a man named by police as Salman Abedi set off an improvised bomb on Monday night as crowds streamed out of a concert.
Terror threat now critical. And 5k troops on streets guarding parliament, stations etc.
— Paul Johnson (@paul__johnson) May 23, 2017
May mentions "Operation Temperer" which has been prepared since 2015 (as The Telegraph details)
More than 5,000 soldiers could be deployed on the streets of Britain in the wake of major terrorist attacks, under a secret Government plan, it has emerged.
The troops would be sent to guard key targets in major cities if Isil or other terror groups launched multiple attacks on UK soil, under the plan, codenamed Operation Temperer.
Details of the operation were disclosed by the Mail on Sunday after accidentally being uploaded to the National Police Chiefs Council website last week.
Officers had been briefed on the plan by Deputy Chief Constable Simon Chesterman, the ‘national lead’ for armed policing, during an NPCC meeting in Leicester in April.
Under the heading ‘counter terrorism post Paris large scale military support to the police’, minutes of the meeting disclosed that up to 5,100 troops could be deployed “based on force assessments of how many military officers could augment armed police officers engaged in protective security duties”.
Soldiers would serve alongside armed police officers to protect against further attacks while plotters were hunted down.
A spokesman for the Ministry of Defence said: “The MOD works closely with other government departments and agencies to ensure that it is able to provide appropriate assistance in response to any security threats, including national security. We keep contingency plans under constant review.”
May says the public should not be "unduly alarmed" and says the deployment is proportional to the situation. The good news is these 'critical' alerts usually do not last long...
The last two occasions the threat level was raised to Critical the alert lasted no more than a few days: pic.twitter.com/GpzWJF4jMX
— Alan Travis (@alantravis40) May 23, 2017
Not exactly reassuring.
— Rami (@RamiAILoIah) May 23, 2017