A 91-year-old whose political activities were covertly recorded by police has won the right to take his legal case to the European court of human rights.



John Catt, who has no criminal record, has fought a six-year battle to force the police to delete their surveillance records of his activities at 66 peace and human rights protests.

The police had noted descriptions of his appearance and clothes at the demonstrations and how he liked to draw sketches of the protests.



The case in front of the European court could help to determine how much information police are permitted to record on law-abiding individuals taking part in protests.



Judges in the court said one of the key questions they would consider is whether the retention of the records was legal and necessary in a democratic society.



Police have been criticised for keeping intelligence files on the political activities of thousands of campaigners, including Green parliamentarians Caroline Lucas and Jenny Jones, and journalists.



The police’s intelligence unit tasked with catching so-called “domestic extremists” says it needs to track large numbers of protesters in case they commit crimes to achieve their political goals.



Catt, a war veteran who has been involved in the peace movement since 1948, lost his legal battle at the supreme court in 2015 after winning in the court of appeal.



On Monday, Catt said: “Denied justice in Britain, I am now taking my fight to Europe in the hope that if successful, the case will set a benchmark in regulating what information the state is legally entitled to collect and retain about lawful protesters, and where unlawfully retained, it should be destroyed.

“I believe that this is a case about the democratic right to protest free from fear of unwarranted police surveillance, retention of data and endlessly being shadowed.”

In 2010, Catt used the Data Protection Act to obtain documents from the secretive police unit.



The documents showed how police had recorded that he “sat on a folding chair … and appeared to be sketching” at one demonstration. Another entry logged that at another demonstration, “he was using his drawing pad to sketch a picture of the protest and police presence”.

An outline of the case drawn up by the European court of human rights records that the police held 66 entries on Catt between 2005 and 2009, mainly relating to his presence at demonstrations against an arms factory in Brighton. They also included his attendance at a demonstration outside the Labour party conference in 2007.



The supreme court ruled that the police had lawfully kept the records on Catt. One of the judges, Lord Sumption, said Catt regularly took part in demonstrations against the Brighton arms factory, owned by the manufacturer EDO MBM, which police had said were “amongst the most violent in the UK”.

Sumption accepted that Catt – “for whom violent criminality must be a very remote prospect indeed” – only took part in peaceful protest.



He added, however, that police needed to assemble a jigsaw of information to prevent and detect crime associated with the demonstrations.



A group of journalists is also taking legal action against the police after discovering that the “domestic extremism” unit had recorded its professional activities on a database.

The group, whose case is supported by the National Union of Journalists, said it was challenging a decision by the police to refuse to disclose the most up-to-date parts of the files to them during the legal action.



Shamik Dutta, of the law firm Bhatt Murphy, who is representing Catt and the journalists, said: “John Catt looks forward to the European court making its decision as a matter of urgency. In the meantime, parliament must recognise – and address – the chilling effect unwarranted surveillance is having on freedom to protest and investigative journalism in the UK.”

The “domestic extremism” unit has changed its name a number of times in the last five years since controversy over the undercover infiltration of political groups erupted following the exposure of police spy Mark Kennedy.

