For those of us who have spent many years fighting excessive and intrusive surveillance of political protest by the state, the victory of John Catt in the Court of Appeal this week was especially sweet. The judgement rules that the gathering and retention of information about John Catt’s political activity was an unlawful breach of his right to a private life, and leaves police intelligence gathering practices in tatters.

John Catt was an 85 year old peace campaigner with no criminal history, known for making sketches at protests. He attended demonstrations against the EDO factory in Brighton called by the organisation Smash EDO where he was noted and identified by the Domestic Extremism Unit – at that time called the National Public Order Intelligence Unit (NPOIU). When he made a subject access request under the Data Protection Act, the NPOIU was found to hold details of his appearance, his vehicle, demonstrations he had attended (not all of which were connected to Smash EDO), and other personal details. His daughter, Linda Catt, also found that her details and presence at the same demonstrations were similarly recorded by the NPOIU.

This sort of data gathering is not unusual. It was revealed at a trial of Fitwatch activists in 2010 that the criteria for taking and retaining photographs were extremely broad. Forward Intelligence Teams would consider a person ‘of interest’, and therefore take and retain photographs of them, if they appeared regularly at protest, appeared to be a prominent individuals or peer leaders, or were seen associating with other ‘persons of interest’. Even MP Jeremy Corbyn and the then interfaith adviser to Nick Clegg, Fiyaz Mughal ended up on the CRIMINT database for their part in a Stop the War protest.

The Catt judgement makes the continuation of these practices problematic for the police. In ruling on the case of John Catt, Lord Justice Moore-Bick commented that

“Having seen copies of various reports in which Mr. Catt is mentioned and the information provided in response to his subject access request, we are left with the clear impression that police officers who attend protests organised by Smash EDO for the purpose of gathering intelligence record the names of any persons whom they can identify, regardless of the particular nature of their participation.”

“One factor of particular importance is whether those data have been subjected to systematic processing and entry on a database capable of being searched in a way that enables the authorities to recover information by reference to a particular person.”

The judgement found that the information on Mr Catt which the police had retained was “information falling within the scope of his personal autonomy over which he is entitled to retain control.” The retention of this information was, in John Catt’s case, disproportionate and unjustified.

This does not, of course, mean the end of police data gathering, just that they will have to justify it on the basis of the threat posed by the individuals they are monitoring. The police will probably still be able to gather all sorts of personal data on anyone who is engaged in direct action (however peaceful) or who have convictions related to protest (however small). But it should, if the police comply with the law, mean the end of routine and systematic gathering, retention and processing of personal data of people present at political protest. It should also mean that others who have no convictions should be able to get their details taken off the database.

Ensuring that the police comply with this ruling presents a whole new set of problems, but the judgement is welcome nevertheless. It is the latest in a series of challenges which, little by little, have opened up surveillance practices to legal and public scrutiny. John Catt should be applauded for his courage and determination in making this happen.