Around 500 live operations involving 3,000 "subjects of interest" are currently taking place in Britain. At the same time there are 20,000 people in Britain who have previously been investigated for terror-related cases and could still pose a threat, Saijd Javid said in his speech.
The massive release of data is meant to boost effective cooperation between the intelligence services and the local police authorities to reduce Britain's vulnerability to potential attacks.
Users online reacted to the news of authorities revealing the data of 20,000 "close subjects of concern."
"One of the lessons learned from the 2017 attacks by security services and by David Anderson QC was we can do better by sharing more of this classified intelligence. It might sound self-evident today, it wasn't really happening before. We will be piloting that through multi-agency centers. We're going to start by piloting in London, West Midlands and Manchester," Mr. Javid told the audience on Monday.
Local agencies, such as neighborhood policing, local councils and probation officers, in those areas will be sharing information in non-classified form, such as biographical information, the Home Office Chief said.
"At a local level these agencies might help with subjects of interests. We want to see what kind of interventions work best," he added.
In his speech Mr. Javid revealed a new blueprint for better national security measures, including plans to keep the government's somewhat controversial counter-terror Prevent strategy.
Created by the Labour government in 2003, Prevent aims to respond to the ideological challenge of terrorism, prevent people from being drawn into terrorism and work with sectors and institutions where there are risks of radicalization. It has been both criticized for isolating and demonizing British Muslims and commended for keeping British communities safe.
The new plan will incorporate lessons from the London and Manchester attacks, which claimed 36 lives in 2017. The threat to the UK was raised twice to the highest level in 2017, and currently remains at"severe."