Select Committee on Science and Technology Fifth Report


The Data Protection Act

  4.15     A fundamental principle behind the Data Protection Act 1984 is that material should be collected for specified and legitimate purposes, and used and disclosed only in ways compatible with those purposes. Yet, as already noted, the Act only applies to CCTV material in the relatively rare circumstance that the data were recorded and processed with respect to an individual.

  4.16     In both written and oral evidence from the Data Protection Registrar (QQ 222-259, p 76) we were struck by the commonality of purpose behind her remit and the objectives which we believe should be applied to the control of CCTV. We share the view that "it is not so much the existence of technology that poses a threat to the civil liberties of the individual, but the use that is made of the technology and the setting in which surveillance takes place" (p 79). The principles of the Act, on the relevance of information, fair processing and disclosure, are just those which should be applied to public space surveillance.

  4.17     As we complete our report a new Data Protection Bill has been introduced in Parliament[28]. We would like to see the new law encompass CCTV and the DPR be given responsibility to issue or oversee enforceable codes of practice for such systems. The maintenance of public support for CCTV would be further strengthened if the DPR were to be given powers to check, that is to audit, the operation of these systems, and not to have to wait for a complaint to be lodged before taking action.

Data matching

Box 6: Image recognition
Most cameras are passive, unintelligent devices which take a picture and leave the processing and interpretation to human operators. If a computer is linked to an image input device (either a camera or a scanner) it is possible to automate some of the interpretation, to speed up the interpretation process dramatically and to cross-match the image to other databases. There are numerous applications of this technology but three have, perhaps, the widest implications for images used as evidence: character recognition from scanned documents, number plate recognition (from images taken by surveillance or enforcement cameras), and face recognition.
Character recognition
Character recognition software is often used in conjunction with document scanners to convert the image into a word processing file. The document is scanned to produce a digital image and then the recognition software interprets areas of text within the image, translating data patterns into appropriate text files. There are a number of advantages over the original scanned image: the new file uses considerably less memory; the document can be treated as any other word processing file, rather than as an image; the quality of the document as displayed on screen is often greatly improved; and the document becomes searchable using standard techniques.
Number plate recognition
This was demonstrated to the Committee by the City of London Police who use a system of cameras to monitor vehicular access to and from a controlled zone within the City. The principle is similar to character recognition discussed above. A camera films the vehicles, software interprets which section of the image is the number plate, and then character recognition software interprets the picture elements to make a 'best guess' of the numbers and letters in the number plate. In the City of London operation the system processes around 114,000 vehicles a day. It takes about four seconds to identify not only the number plate, but also to cross-check it with local Police databases and the Police National Computer and then alert the control centre operators if there is a match (eg if the vehicle has been registered as stolen). The recognition software does make errors and so the video still image of any number plate which is difficult to identify (eg obscured by mud), and any number plate which is flagged for further attention because it cross-matches with a database entry, is displayed in the control room alongside the interpretation for human verification.
Face recognition
Face recognition is still in the development stages because of the scale of complexity involved. As well as needing to define what makes faces different enough for a computer to distinguish individuals, a reliable system would have to overcome differences in facial expression, head angle, lighting, movement, and ephemeral features such as sun tans, hair style, facial hair, make-up, hats and sunglasses too! A comparative database of faces identified with individuals is a prerequisite, and such a database may need to contain multiple images of each person: a database of this kind does not exist, and there might be intense opposition if it were attempted to create one.

  4.18     The Government is looking at the provision of electronic services and these are measures we firmly support. Data matching is a particular concern for this Enquiry where image recognition techniques are used (see Box 6). In the City of London we saw a number plate matching system in operation and we were impressed by the speed with which it could process vehicle information. The Symonds Group held the view that: "if cameras are used in conjunction with image tracking software then the effectiveness of surveillance is vastly improved and thus the implications of civil liberties are increased" (p 151). If the technology continues to develop as expected it may in the future be possible to match data from the digitised passport photographs that are coming into use (p 127) with other databases, enabling the rapid identification of individuals who were, for example, attending a football match. This might cause justifiable unease. It is clear that image recognition technologies have an important role to play in assuring security, but controls on their use may be needed to strike a fair balance with civil liberties.

  4.19     Although we did not take evidence and did not consider all of the issues of image recognition and data matching in detail, it is an area where the technology is pressing ahead and the public debate lagging far behind. It is possible that there will be disquiet over the implications of data-matching in general and image recognition in particular. We were therefore surprised that there was no published guidance for Government Departments on data-matching and related technologies (p 171).

  4.20     We recommend the Government produces guidance for both the public and private sectors on the use of data matching, and in particular the linking of surveillance systems with other databases.

  4.21     Individuals may not be aware of the existence of information on them derived by reference to two or more unrelated databases. They will therefore not recognise if there is a need to approach the DPR who can act only if a complaint has been made. We recommend that the DPR be given powers to audit the operation of datamatching systems.


  4.22     Any form of surveillance is also a form of intrusion. The question to be considered is whether such intrusion can be justified (p 151). In this chapter we sought ways to harmonise the interests involved. An individual's right to privacy and the interest of both the individual and society in the prevention of crime and disorder need to be fairly balanced. Essential and unavoidable compromises must be widely appreciated. Our recommendations for a degree of greater control over the installation, use and release of images from public space surveillance systems seek to chart a way to achieve that balance. We want to see public acceptance of surveillance, introduced to deter and assist in the capture and prosecution of criminals, blossom and flourish. This is more likely to be the case if there is wide public debate of the issues involved, and we recommend that the Government should promote such debate.

28   The Data Protection Bill, HL Bill 61, 14 January 1998 Back

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