Undercover officers secretly monitored a community organisation that sought to expose wrongdoing and corruption in the Metropolitan police, the spycops public inquiry has heard.

Previously secret reports show that the Hackney Community Defence Association (HCDA) in east London and its key organiser were monitored by police spies for a decade.

The HCDA helped victims of police violence to successfully take legal action against the Met as a way of holding them to account. The organisation also helped to uncover key evidence of a major alleged corruption scandal involving the police.

The surveillance reports contained personal information about Graham Smith, who founded and ran the HCDA, including his marriage and his father’s terminal cancer.

The judge-led inquiry is looking at the conduct of undercover police officers who spied on thousands of predominantly leftwing campaigners between 1968 and at least 2010. It was established after revelations of misconduct.

It heard that undercover officers compiled 44 reports which had details of the activities of the HCDA and Smith between 1988 and 1998. The first was filed in August 1988, a month after the HCDA had been set up.

The organisation was established to counter police brutality and racism. It operated as a self-help group which enabled victims of police violence to use lawsuits as a means of obtaining justice. Over time, the HCDA highlighted a series of cases which were regularly publicised in the media.

It also helped in the 1990s to expose one of the worst alleged cases of police corruption in which officers at Stoke Newington station were accused of planting drugs on people, selling drugs, theft and other crimes.

The Met has conceded that it was wrong for senior officers to have directed undercover officers to spy on the HCDA. It and other groups “were engaged in legitimate activities, including seeking to hold the [Met] accountable for its own conduct and decision making, the force said.

Giving evidence on Thursday, Smith said many of the surveillance reports were inaccurate. One said the HCDA had obtained a scanner to listen into police communications and was “particularly interested in monitoring the activities of a Hackney police unit headed by a sergeant which it believes is specifically targeting anarchists in the area”.

Smith said: “I don’t know anybody in HCDA who was in possession of a radio scanner,” and that the undercover police had wrongly sought to portray the organisation as being run by anarchists.

One of the undercover officers, Mark Jenner, started a five-year deployment in Hackney in 1995. The strategy document outlining the groups he was sent to infiltrate specifically referred to the HCDA, which was described as being “involved in co-ordination of opposition to … local police (allegations of harassment, racism, wrongful arrest, etc).”

In the document, his managers said the HCDA was “probably not worthy of monitoring in terms of [its] own importance”, but would be “suitable vehicles for an undercover officer establishing an anarchist reputation”.

Smith rejected suggestions that the surveillance of the HCDA was an incidental byproduct of the covert deployments.

He said the undercover officers “sought to deflect from their unlawful collection, recording and retention of intelligence by labelling the police accountability campaigns they targeted as political extremists”.

Jenner passed personal information about Smith to his managers. This, Jenner has said, was done to update the secret file on Smith that was maintained by special branch, the secretive police division that monitored political activists.

Special branch, which employed the undercover officers, started keeping confidential files on the HCDA itself to log its activities in 1988, the year it was founded.

Another undercover officer, Trevor Morris, was deployed in 1991 to spy on groups in Hackney for four years. Outlining the purpose of his covert work, his managers referred to issues such as “anti-police matters”, and said the HCDA was one of the groups he would be monitoring “in order to assess their level of activity and potential involvement in future issues”.

Smith said he believed a significant number of surveillance reports on himself and the HCDA had not been disclosed to him.

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