Jonathan Russell is head of policy at Quilliam, a counter-extremism organization based in London. The opinions in this article belong to the author.

(CNN) One immediate consequence of the terror attack in Manchester on Monday night is the escalation of the terror threat level in the United Kingdom to "Critical."

Independently set by the Joint Terrorism Analysis Centre (JTAC), "Critical" means an attack from jihadist terrorism is expected imminently. It also means that Operation Temperer, which allows up to 5,000 military personnel to support the police on British streets, will be activated for the first time.

This is a point of departure for Britain. Prime Minister Theresa May has reminded the British public to remain vigilant, but has insisted that she doesn't wish for people to be unduly alarmed.

What affect will this have? Can Britain learn from other countries that have taken similar approaches before? And what more needs to be done to keep Britons safe?

The first question is one of resourcing and reassurance. Freeing up the police to investigate the network that possibly surrounds the attacker Salman Abedi, follow various intelligence leads and prevent copycat attacks from occurring is certainly a positive step.

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