Campaigners have welcomed today’s victory by veteran peace campaigner John Catt against the misuse of personal data collected via police surveillance.

John, who is well known for his work with groups such as Smash Edo, has spent eight years on the case, taking it all the way to the European Court of Human Rights which has now found that police have been unlawfully stacking information about protesters on its Domestic Extremism Database.

The court ruled that keeping details about John indefinitely on a searchable database breached Article 8 on respecting the right to a private and family life. A 94-year-old committed pacifist, John has no history or prospect of committing any violent activities. In a statement he said:

I now expect police forces nationally to respect this ruling, destroy any data they hold on me, on other peaceful protestors and also journalists who are on the database and ensure they focus their resources more wisely in future.”

I also await a full explanation from the police as to why they failed to disclose all the information they held about me to the Supreme Court in the course of my legal challenge in the UK.

Analysing the ruling, campaign group The Network For Police Monitoring wrote:

Today’s important ruling says the police have been unlawfully retaining personal data on political campaigners on grounds that are too vague and are wholly unjustifiable.

The judgment does not stop surveillance at protests completely, but it does say there are no rules or safeguards on keeping data collected by the police on political campaigning.

It also says that the police appear not to have even respected their own entirely arbitrary definition of “domestic extremism” in deciding to unnecessarily retain information on Brighton campaigner John Catt.

This case highlights concerns Netpol has raised repeatedly over the last decade about the extremely flexible misuse of the “extremist” label against political activists and the unlawful retention of information about them by the police.

Netpol intervened when the case was heard at the Supreme Court in December 2014 and called its ruling in 2015 “judicial approval for the mass surveillance of UK political activism“.

The decision of the ECHR demands action. The time has come for the police to now abandon the meaningless and arbitrary categorisation of campaigners as “domestic extremists” and close down their secretive databases.

Another way to provide the “heightened level of protection” the ECHR says political opinions need from surveillance is the complete separation of public order policing from counter-terrorism units – they have no business involving themselves with legitimate political campaigning

Freedom to protest is threatened by constant, unnecessary and intrusive surveillance, which the ruling acknowledges can have a chilling effect on participation.

Campaigners now also need stronger legal protections, including strict limits on filming and other overt intelligence-gathering tactics at demonstrations.

John initially opened the case after having his request for data deletion denied by the Association of Chief Police Officers, which at the time was overseeing the surveillance initiative. The database, which is run by the National Public Order Intelligence Unit, is now under the command of the Metropolitan Police Commissioner.