Harry Kinmonth reviews a recent Supreme Court judgment which considered the police use of personal data
In R (Catt) v Commissioner of Police of the Metropolis and ACPO and R (T) v Commissioner of Police of the Metropolis  UKSC 9, a decision handed down in early March, the Supreme Court decided that the police were entitled to retain personal data regarding a 91-year-old peace activist and a woman who got into a minor dispute with a neighbour, even though in both cases the individuals' rights to privacy under Article 8 of the European Convention on Human Rights were engaged.
The first of the two linked appeals related to Mr Catt, an elderly man from Brighton who has been active in the peace movement since the 1940s and, during that period, has attended numerous public demonstrations. This has included demonstrations where a minority have resorted to violence (including a rather ominously named group called 'Smash EDO'); although Mr Catt himself never engaged in any violent behaviour and has never been convicted of any offence. Purely as a result of his recorded attendance at such demonstrations, he found that certain information about him had been included on the so-called 'Domestic Extremism Database'.
The second appeal related to Ms T, who got into an argument with a neighbour which resulted in the police sending a letter informing her that an allegation of harassment had been made against her (no further steps were taken). Records of this letter were then retained on police databases.
Interestingly, both cases involved personal data consisting entirely of records made of actions that had taken place in public (ie Mr Catt's actions at public protests and Ms T's actions in common spaces of a block of flats).
The Supreme Court proceeded on the assumption that the state's systematic collection and storage in retrievable form even of public information about an individual engages Article 8(1) as an interference with private life. The question to decide was therefore whether this interference was permitted under the exception in Article 8(2) on the basis that: (a) the retention of the data was 'in accordance with the law' and (b) it was 'necessary', in that it was proportionate to the objectives concerned.
Regarding the first question, Lord Sumption, who gave the leading judgment, reviewed how the police powers to obtain and store information are regulated (ie via the Data Protection Act 1998 and various codes of practice and guidance that have been issued on the Act's application to police powers) before concluding that the police's data retention regime was in accordance with the law.
This left the key question in the appeals of whether the interference with Mr Catt and Ms T's Article 8 rights on the facts of each case was proportionate to the objective of maintaining public order and preventing or detecting crime.
In Mr Catt's case, the Court found (Lord Toulson dissenting) that the interference was proportionate. Lord Sumption gave some important guidance (at ) on how intelligence gathering should be viewed in the context of the Data Protection Act 1998. He also emphasised (at ) that, just because Mr Catt had not committed and is not likely to commit an offence, that does not make the information held on the database about him irrelevant:
'the material is relevant not primarily for the purpose of establishing criminality against Mr Catt but for the purpose of studying the methods and organisation of a violent organised group whose demonstrations he attends.'
Lord Toulson dissented on the basis that he did not think police investigations would be hampered by information such as this being deleted from their databases. He felt that the deletion of this data was further justified in this case given that Mr Catt was doing no more than exercising his democratic right to peaceful protest: 'in a modern society the state has very extensive powers of keeping records on its citizens. If a citizen's activities are lawful, they should be free from the state keeping a record of them unless, and then only for as long as, such a record really needs to be kept in the public interest'. Unfortunately for Mr Catt, Lord Toulson was in a minority of one.
In Ms T's case, the Court observed that the record of her being sent a warning letter was only kept for two and a half years (albeit that the general policy allowed such material to be kept for up to 12 years). Their lordships came to the view that there were very good reasons to keep records of cases involving harassment, and that the interference with her rights in this particular case was proportionate. As Lady Hale explained (para 54):
'particularly in disputes between neighbours and in cases of domestic ill-treatment and abuse, the police response to a new complaint will be affected by knowing whether other complaints have been made in the past against the same person… Domestic violence often escalates in seriousness with each new incident, and the police have to be aware of this when considering how to respond.'
This decision provides yet another example of the courts trying to strike a balance between the need to protect individuals' Article 8 rights and the need to allow other competing interests to be pursued (here the detection of crime) in a society where increasing volumes of data can and are being collected and retained in searchable form. While the case provides important guidance on the retention of personal data by the police, it also is of interest for the following broader reasons:
1. The judges made it very clear that a complainant's first port of call when they believe there has been a breach of their data privacy rights should be the Information Commissioner (see  in particular), with the hint that there may be costs implications for those who decide to go to court instead.
2. The balance that any particular judge will strike between Article 8 and the multitude of competing rights and interests on the facts of a particular case is, as we well know, extremely hard to predict. The fact that such eminent judges as Lord Sumption and Lord Toulson reached very different conclusions on the facts of Mr Catt's case is just the latest example of this.
3. The perception a particular judge has of a data controller's resources is likely to have an impact on how the balance is struck. Lord Sumption concluded that, even if the police had not been entitled to retain the information as they did, the labour involved in reviewing their databases in order to ensure people like Mr Catt were excluded 'would be disproportionate to the value of the exercise' and would be 'a major administrative exercise' which would not be justified. However, no evidence appears to have been provided by the police to show they would not be able to cope with such a task. It seems that Lord Sumption may have assumed that the police, being a public body funded by the taxpayer, would not be able to handle too onerous an obligation to weed out irrelevant and outdated information from their databases. This contrasts with the assumptions other decision-makers have made of certain large private data controllers; namely that they are large enough, rich enough and sophisticated enough to be expected to cope with very significant administrative burdens in order to comply with their data protection obligations (the Costeja decision being the obvious example). Regardless of whether or not either of these assumptions is justified, it gives some indication of the sorts of perception issues which are impacting on decision-making in this greyest of grey areas.
Harry Kinmonth is a Senior Associate in RPC's media disputes team and has a particular interest in data privacy issues.