BRITAIN's threat level has been reduced from "critical" to "severe" four days after the Manchester bombing which claimed 22 lives.

Operation Temperer, which allows the military to be deployed to key sites, will continue until the end of the bank holiday, Prime Minister Theresa May said.

4 The UK's terror threat level gives a broad indication of how likely an attack is, based on a range of factors Credit: Getty Images

4 Armed police have been carrying out a series of raids since Monday's attack Credit: PA:Press Association

However after the Bank Holiday the members of the military which have been deployed on the UK's streets will be withdrawn.

There are five threat levels, decided by the Joint Terrorism Analysis Centre, designed to give a broad indication of the likelihood of an attack.

Britain's threat level was upgraded from "severe" to "critical" on May 23 following the Manchester bombing the previous day.

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The last time the threat level was deemed "critical" - the highest level - was in June 2007.

Speaking this morning, Mrs May said: "To provide maximum reassurance to the public Operation Temperer will continue to operate until the Bank Holiday concludes.

"Then from midnight on Monday onwards there will be a well planned and gradual withdrawal of members of the armed forces who will return to normal duties."

Following the statement, the country's most senior counter-terror officer Mark Rowley said that there "will be more arrests and more searches".

What do the threat levels mean? LOW means an attack is unlikely.

MODERATE means an attack is possible, but not likely

SUBSTANTIAL means an attack is a strong possibility

SEVERE means an attack is highly likely

CRITICAL means an attack is expected imminently

The de-escalation came as a street in Manchester's Moss Side was evacuated by counter-terror officers. Boscombe Street was said to been cleared on Saturday morning, with one witness describing a bomb-disposal van parked at the junction with Yew Tree Road.

An address in the area was being searched by detectives as they sought to close the net on the suspected terror cell behind Abedi.

Yamma Wu, 29, said she had been ordered not to leave her house by officers.

He said: "I can see police cars outside the street and they are not allowing people out or in and there is an evacuation in this area, but because I have got a little baby with me they told me I could say inside, but I could not go out."

4 Prime Minister Theresa May yesterday giving a press conference during the Summit of the Heads of State and of Government of the G7 Credit: Getty Images

The announcement came as Manchester was dubbed a "global symbol of courage, defiance and unity" by former PM Gordon Brown.

The ex-Labour leader said the attack has broken hearts "but our resolve remains unbreakable".

In a General Election speech in Greenock today, Mr Brown paused to remember the 22 people who died and the dozens injured in the Manchester Arena bombing on Monday night night.

Wounded concert-goers are treated by emergency workers after the suicide bomb attack at the Manchester Arena Credit: PA:Press Association

4 The last time the UK threat level was upgraded to critical was just before the 7/7 bombings Credit: Getty Images

He said: "Today, and in the days and weeks ahead, we will shed tears at the loss of so many children and young people at the hands of terrorists.

"Children, teenagers, young parents - too many lives have been taken, but I say they cannot take our unity, our solidarity, our support for each other.

"Hearts are broken, but our resolve remains unbreakable.

Greater Manchester Chief Constable Ian Hopkins gives briefing following Manchester Arena explosion Credit: PA:Press Association

"Lives have been destroyed, but our spirit is indestructible.

"They thought that we would give in, but we have showed that we keep going.

"In the hours and days following the attack, Manchester has become a worldwide symbol of courage, defiance and unity.

"To those who are doubters and who believe that terrorism will make us weak through fear, divide our communities and shatter our spirit, let them go to Manchester."

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