High Court judges are now deciding whether a covert police unit - already tarnished by the Mark Kennedy controversy - should be keeping secret files on an 87-year-old pensioner

Two High Court judges have retired to consider their verdict in a landmark court case over secret surveillance files.

The judges are mulling over whether police chiefs should be allowed to keep a detailed record of the political activities of John Catt. Their ruling will help to define what powers the police should have to keep secret files on political activists. Their verdict is expected to be delivered in a few weeks.

Here and here are two reports which we published yesterday on the hearing, while some earlier stories can be found here and here.

John (and his daughter Linda) were the first people who were known to have obtained their files from the database of campaigners compiled by the National Public Order Intelligence Unit.

This has been a striking case. Remarkably the first files to emerge from the database threw up a case which landed police chiefs in the High Court (to their possible embarrassment). The files showed that the police had kept an extensive record of an 87-year-old pensioner who has no criminal record. Furthermore, the police had kept notes of how the pensioner had a habit of turning up to demonstrations, taking out his sketch pad and drawing the scene.

In all, they had logged his activities at more than 55 demonstrations over a four-year period.

The police chiefs running the NPOIU say that they are monitoring activists who are "domestic extremists" - people they say who carry out "criminal acts of direct action in furtherance of what is typically a single issue campaign".

But the first glimpse of those on the database revealed something which appeared very different to that. As his supporters argue, John Catt is a country mile away from a hardcore political criminal.

He certainly did not look as if he was a great threat to the state as he followed yesterday's legal proceedings with the help of headphones to amplify the barristers' arguments.

The revelation of his files immediately raised the issue of who else is being recorded on the NPOIU database on questionable grounds.

John and Linda Catt found out what files the NPOIU had compiled on them entirely lawfully, through the data protection act. Individuals who think they are on the NPOIU database can request copies of the files held on them through this act. All they need to do is submit a letter asking for their files to the Metropolitan Police, with a ?10 cheque.

We have published a handy guide on how to submit these data protection requests. It has, for example, a sample letter. The guide can be found here. We are always interested to see what is disclosed to individuals if they don't mind sharing it with us.