Greater Manchester is one of three areas piloting a new anti-terror scheme in which MI5 will share information about "subjects of interest" with local police and councils.
It follows a review of recent attacks including the Manchester Arena bombing.
Those behind the scheme say greater intelligence sharing will minimise the threat posed by suspects who are rapidly radicalised before security services can detect the change.
Theresa May said the new strategy "has a much greater focus on systemic co-ordination across the public sector".
"By linking up not just the intelligence agencies but also local authorities, health providers and many others, it will make it harder than ever for terrorists and those who support them to plan and carry out attacks."
Salman Abedi, the Manchester bomber, was categorised as a "closed subject of interest" at the time of the attack, and so not under active investigation.
There are an estimated 20,000 individuals who have previously featured in terrorism probes, either as active targets or on the periphery of inquiries.
Officials emphasised that the new project will be on a much smaller scale - with the number of cases where intelligence could be shared expected to be in the low hundreds over the next year.
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The family of a young man killed in the Manchester Arena bombing have joined others affected by terrorism to set up a new campaign group.
29 year old Martyn Hett was one of the 22 people murdered in the Manchester Arena attack.
His brother and mother have helped to found the 'Survivors Against Terror' group, which launches today.
Its members want better support and more effective government policies to tackle terrorism.
Our collective view is that terrorism can be defeated, but only if we pull together as a country to fight it more effectively.
We will work to build a voice for survivors.
The group plans to conduct a survey of those affected by terrorism, and to go into schools to talk to children about the impact of hatred.
They want to make sure support is consistent for victims across the country.
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Relatives of those killed in terror attacks, including the Manchester Arena bombing, are working with attack survivors to campaign for more help for victims.
The 'Survivors Against Terror' group will be launched today. Its members want better support and more effective government policies to tackle terrorism
A man has been charged with terrorism offences after being arrested in Lancashire last month.
Husnain Rashid, of Leonard Street in Nelson, has been charged with two offences under Section 5 of the Terrorism Act 2006 - engaging in conduct in preparation for terrorist acts.
Greater Manchester Police said the 31-year-old would appear at Westminster Magistrates' Court in London on Wednesday.
Rashid was arrested on Wednesday November 22 as officers from Lancashire Police and Counter Terrorism Policing carried out raids on two properties in Leonard Street.
Speaking at the time, Assistant Chief Constable Tim Jacques, of Lancashire Police, said: "I recognise that events like this can cause people to worry and impact on wider public confidence.
"I want to reassure people that our information and intelligence lead us to believe that there is no immediate threat to local people."
A report's due to be released about how MI5 and the Police handled intelligence ahead of the terror attacks in Manchester and London this summer.
The Anderson Report is expected to recommend how the security services can minimise the chances of missing potential attackers in the future.
Following attacks at Westminster, Manchester, London Bridge, and Finsbury Park, MI5 and the police launched internal reviews to:
- Consider what was known about the perpetrators prior to the attacks;
- Examine decisions made regarding any intelligence held before the attacks took place;
- Identify areas for improvement, such as in the management of thousands of individuals who have been looked at as part of previous inquiries but who are not currently under active investigation.
The assessments have been carried out internally but David Anderson QC was appointed by the Government to provide "independent assurance"
It emerged that perpetrators of the Westminster and Manchester atrocities, as well as one of the London Bridge attackers, had at some point been on the radar of authorities - although none was considered high risk at the time of the attacks.
In a speech in October, the head of MI5 Andrew Parker said that when an attack happens "we are determined, using the harsh light of hindsight, to squeeze out every last drop of learning so that we can be the very best we can be, now and in the future."
The scale of the current threat is seen as unprecedented.
Counter-terror teams are running about 500 live investigations involving 3,000 individuals at any one time, while there is also a wider pool of 20,000 former "subjects of interest" who must be kept under review.
It is understood police and MI5 have foiled nine plots since March, in addition to the terrorist incidents that have occurred.
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