On 4 March 2015 the Supreme Court (Lord Neuberger, Lady Hale, Lord Mance, Lord Sumption and Lord Toulson) handed down its judgement in joined cases Catt and T v Commissioner of the Police of the Metropolis and Another  UKSC 9. The appeals stemmed from a complaint from Mr Catt that information collected and retained by the police in relation to his lawful participation in a number of political protests over many years was contrary to his right to respect for private life protected by Article 8. Ms T complained that retention by the police of a "Protection from Harassment" letter issued to her after a complaint from a neighbour also amounted a violation of her right to respect for private life under article 8.
The Court was unanimous that the systematic collection and retention of information about Mr Catt and Ms T constituted an interference with their right to respect for private life under article 8(1), even though, in the case of Mr Catt, the information collected related to his activities in public. They also agreed that the combination of the requirements of the Data Protection Act 1998, coupled with the Code of Practice issued by the Secretary of State under the Police Act 1996 and the detailed Guidance on the Management of Police Information issued by the Association of Chief Police Officers, provided sufficient protection against arbitrary policy behaviour, so that the collection and retention of this information was "in accordance with the law" for the purposes of Article 8(2) of the Convention.
The crucial issue in both cases was whether the retention of the data in relation to Mr Catt and Ms T was a proportionate interference and therefore justified as ‘necessary in a democratic society’ for the purposes of Article 8(2).
The majority of the Court (Lord Toulson dissenting) held that the retention of data in relation to Mr Catt was proportionate. Given that the nominal record relating to Mr Catt had been deleted some time ago, all that remained were the incidental references to his presence at certain demonstrations in information reports about those demonstrations and nominal records relating to other people. The majority held that this information can be useful to the police, and that the amount of labour required to delete incidental information about Mr Catt would be disproportionate. Lord Toulson held that there was insufficient evidence that requiring the police to constantly review the utility of information held about individuals is too burdensome and that "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."
In relation to Ms T, the Court was unanimous that the retention of data was proportionate. Lord Sumption, with whom Lord Neuberger agreed, described the letter as "unnecessarily accusatorial and menacing" but held that it served a legitimate policing purpose. He held that retention in line with the Metropolitan Police policy of such information for twelve years would have been unlawful, but that the two and a half years for which the letter was in fact held before it was destroyed was not disproportionate, albeit it was "at the far end of the spectrum". Lord Toulson, with whom Lady Hale and Lord Mance agreed, held that, given the wide spectrum of offensive behaviour caught by the Protection from Harassment Act, and the fact that the response of the police to complaints about abusive conduct may well be affected by knowing whether similar earlier complaints have been made against the same person, either by the same or by other complainants, it is lawful for the police to adopt a standard practice of retaining a record of such complaints for twelve years, but with a readiness to be flexible in the application of the practice.
Paul Bowen QC and Zahra Al-Rikabi acted for Ms T, instructed by John Halford of Bindmans LLP.