This is the third time the threat level is raised to "critical," and the police hope it will not last for a long time.
There are five level of terrorist threat – "low," "moderate," "substantial," "severe" and "critical." The scale was introduced in 2006, and the level of terrorist threat has never been lower than "substantial" since.
THIRD TIME IN HISTORY
On June 30, 2007, the level was raised again after three terrorist attack attempts in 36 hours in London and Glasgow. The threat level remained at "critical" until July 4.
According to the UK Security Service, the "critical" level means that an attack is expected imminently, while "severe" level indicates an attack is highly likely. The "substantial" level means an attack is a strong possibility.
ARMY ON THE STREETS
Prime Minister May also announced that Operation Temperer was now in force, allowing members of the armed forces to be deployed to key civilian sites.
According to media reports, some 5,000 military servicemen may be deployed within the Operation Temperer.
London Mayor Sadiq Khan called on the population to remain vigilant and report anything suspicious to the police.
"There will be additional police officers on London's streets over the coming days — including additional armed officers. You will also see some military personnel around London — they are there to help our police service to keep us safe and guard key sites," Sadiq explained.
SUSPECT BORN AND RAISED IN UK
Also, a 23-year-old man was detained in Manchester in connection to the attack, Greater Manchester Police Chief Constable Ian Hopkins said, with Prime Minister May stating that there is a strong possibility that "a wider group of individuals" was linked to the attack.
May called on the people to "be vigilant and to co-operate" with the police, pledging to take every measure available and provide the police and security services with every additional resource to protect the public.
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