Ed Husain of the anti-extremism group Quilliam and Shami Chakrabati of Liberty on how the community engagement scheme is being used to gather personal information guardian.co.uk

The government programme aimed at preventing Muslims from being lured into violent extremism is being used to gather intelligence about innocent people who are not suspected of involvement in terrorism, the Guardian has learned.

The information the authorities are trying to find out includes political and religious views, information on mental health, sexual activity and associates, and other sensitive information, according to documents seen by the Guardian. Other documents reveal that the intelligence and information can be stored until the people concerned reach the age of 100.

Tonight Shami Chakrabarti, director of Liberty, branded it the biggest spying programme in Britain in modern times and an affront to civil liberties.

The intelligence is being gathered as part of the strategy Preventing Violent Extremism – Prevent for short. It was launched three years ago to stop people being lured to al-Qaida ideology and committing acts of terrorism.

The government and police have repeatedly denied that the £140m programme is a cover for spying on Muslims in Britain. But sources directly involved in running Prevent schemes say it involves gathering intelligence about the thoughts and beliefs of Muslims who are not involved in criminal activity.

Instances around the country include:

• In the Midlands, funding for a mental health project to help Muslims was linked to information about individuals being passed to the authorities.

• In a college in northern England, a student who attended a meeting about Gaza was reported by one lecturer as a potential extremist. He was found not to be.

• A nine-year-old schoolboy in east London, who was referred to the authorities after allegedly showing signs of extremism – the youngest case known in Britain. He was "deprogrammed" according to a source with knowledge of the case.

• Within the last month, one new youth project in London alleged it was being pressured by the Metropolitan police to provide names and details of Muslim youngsters, as a condition of funding. None of the young Muslims have any known terrorist history.

• In one London borough, those working with youngsters were told to add information to databases they hold to highlight which youths were Muslim. They were also asked to provide information, to be shared with the police, about which streets and areas Muslim youngsters could be found on.

• In Birmingham the programme manager for Prevent is in fact a senior counter- terrorism police officer. Paul Marriott has been seconded to work in the equalities division of Britain's biggest council.

• In Blackburn, at least 80 people were reported to the authorities for showing signs of extremism. They were referred to the Channel project, part of Prevent.

• A youth project manager alleges his refusal to provide intelligence led to the police spreading false rumours and trying to smear him and his organisation.

• One manager of a project in London said : "I think part of the point of the [Prevent] programme is to spy and intelligence gather. I won't do that." In another London borough wardens on council estates were told to inform on people not whom they suspected of crimes, but whom they suspected could be susceptible to radicalisation. One source, who has been involved in Whitehall discussions on counter-terrorism, said: "There is no doubt Prevent is in part about gathering intelligence on people's thoughts and beliefs. No doubt." He added that the authorities feared "they'd be lynched" if they admitted Prevent included spying.

Ed Husain, of the Quilliam Foundation, who has advised both Labour and the Conservatives on extremism, said: "It is gathering intelligence on people not committing terrorist offences." Husain, whose group receives £700,000 in Prevent funding, believes it is morally right to give law enforcement agencies the best chance of stopping terrorists before they strike.

Serious concerns that the Prevent programme is being used at least in part to "spy" on Muslims have been voiced not just by Islamic groups, but youth workers, teachers and others. Some involved in the programme have told the Guardian of their fears that they are being co-opted into spying. They did not want to be named, fearing they would lose their job.

Some groups have refused its funding. In several areas the provision of funding is explicitly linked to agreeing to sharing of information, or intelligence, with agencies including law enforcement.

Traditionally in Britain intelligence is gathered by the police and security services. Prevent is trying to turn community, religious and voluntary groups into information or intelligence providers.

Prevent is run by the Office for Security and Counter Terrorism, part of the Home Office. It is widely regarded in Whitehall as being an intelligence agency.

The OSCT is headed up by Charles Farr, a former senior intelligence officer, with expertise in covert work. Also senior in the OSCT is another former senior intelligence officer. The Guardian has been asked not to name him for security reasons.

Chakrabarti said she was horrified by the revelations. "It is the biggest domestic spying programme targeting the thoughts and beliefs of the innocent in Britain in modern times," she said.

"It is information-gathering directed at the innocent and the spying is directed at people because of their religion, and not because of their behaviour."

The Home Office said: "Any suggestion that Prevent is about spying is simply wrong. Prevent is about working with communities to protect vulnerable individuals and address the root causes of radicalisation."