Caught Looking

August 31, 1998

Angus Hamilton reports on a recent case. Heruns his own firm in North London which specialises in criminal litigation, dataprotection and the regulation of the Internet. He can be contacted at

In April 1998 I represented a young man in his local magistrates’ court onan allegation of possessing indecent photographs of children.

The brief facts of the matter were that in mid 1997 the man had taken hismalfunctioning PC into PC World for repair. The staff there had ‘discovered’a number of files on the hard disk of the machine which contained the indecentphotographs. They had called the police and the man (who for the sake ofanonymity I will call Simon) was arrested in the store.

When interviewed by the police Simon indicated that he did not understand howthe image files got on to his hard drive. He accepted browsing the WWW and also,out of morbid curiosity, visiting some of the more extreme sites on the Internetbut adamantly denied deliberately downloading any such images onto hiscomputer’s hard drive.

What neither he nor the police (nor indeed, it would appear, PC World’sstaff) were aware of at the time of that first police interview was the cachingfunction of the browser software. This, as the computer literate amongst us willbe well aware, ‘snatches’ a copy of whatever is being looked at on the WWW,including images, and stores it in the cache directory of the browser software.The reason for this is not, of course, to facilitate the downloading of materialfrom the WWW but to speed the browsing system up. If you re-visit a particularsite then the browser software takes most of the information from the cache andonly downloads any new material from the WWW site to display the contents of thecurrent site.

Simon was duly prosecuted for possessing indecent photographs of childrenunder s160 of the Criminal Justice Act 1988 (see below for the relevantstatutory provisions).

By the time the case was ready for trial the police had obtained their owndetailed forensic evidence which explained the function of browser software. Theevidence also indicated that, because of the location of the particular imagefiles (in the Netscape cache), it was extremely unlikely that these images weredeliberately downloaded – rather they were almost certainly there as a resultof an automatic function of the browser software.

The Prosecution Case

Despite their own evidence on this point, and despite representations made onbehalf of Simon, the authorities decided to proceed with the prosecution and thematter came before Simon’s local magistrates’ court for hearing in April 1998.

Because of the forensic evidence obtained by the police the Crown ProsecutionService chose to put their case on three mutually exclusive bases.

  • That, despite the location of the image files in the cache directory, Simon had deliberately downloaded the images and then put them there to conceal his actions.
  • That Simon must have been aware that the browser software had the function of automatically downloading material from web sites into a cache directory and consequently must have been aware that by simply looking at such material on the WWW he would thereby come into possession of it.
  • That even if he was not aware of the automatic function of the browser software he nonetheless could be held to have been in possession of such material because the image he looked at on the WWW had been on his computer screen and he had consequently at that point been ‘in possession’ of the image.

Anyone with a basic knowledge of the criminal justice system is probablyaware that the onus is on the prosecution to prove their case beyond areasonable doubt – ie the court must be sure of the relevant facts beforeconvicting. It may seem odd, therefore, that the prosecution could present theircase on three mutually incompatible bases and yet still invite an inference ofcertainty. This tactic however is not wrong in principle – the case can bepresented in the form of incompatible scenarios and the court invited to selectone if they are sure that it represents the facts of the actual situation. Ofcourse if there is uncertainty about all of the scenarios then there must be anacquittal.

Much of the evidence of this particular case was agreed. It was accepted thatthe photographs were indecent and did involve children. It was also acceptedthat the offending articles were found on Simon’s computer. The principalargument was about how they got there. Ironically most of the squabbling was notbetween the defence and the prosecution but between the prosecution’s ownwitnesses. The split basically came between the witnesses from PC World and thepolice technical witnesses. The former, quite bizarrely, were collectivelyadamant that the only way the image files could have arrived on the computer’shard disk was by deliberate downloading. The caching function of the browsersoftware was specifically denied. It was this insistence, the police accepted,that had prompted the investigation and prosecution in the first place. The PCWorld staff also claimed that the image files were found during the computer’srepair because the re-installation of software may have damaged the customer’sdata files and they were therefore checking to see what data files were on themachine before re-loading any software. Apparently they always look for imagefiles first as they are the ‘most common’.

The Defence

Simon defended the case on two bases.

First, it was contended that to ‘possess’ something requires an elementof knowledge of possession – in other words you can only be deemed to be inpossession of an article if you are aware of its presence. The classic exampleis that of a person who unknowingly has something slipped inside their pocket orhandbag. On a strict interpretation that person might be viewed as being inpossession of the ‘thing’ on the basis that they have it about their person.The courts have held that such a strict interpretation would have obviouslyunfair consequences and that, in such a scenario, the individual could not beheld to be in possession because they did not know the ‘thing’ was there.There are limits to such a principle however – it is not a defence to claimthat you had forgotten you were in possession of something you initially knewabout. It may also not assist to say that you were mistaken as to the nature ofthe ‘thing’ you possess – so for example if you are given a sealed packageto carry and told it is cannabis but it later turns out to be heroin you couldbe found guilty of possessing the latter substance. In Simon’s case we arguedthat the browser software effectively slipped the image files into the cache‘pocket’ of the computer without the user’s knowledge.

The second line of defence was the ‘statutory’ defence set out ins160(2)(c) – that the photograph was sent to him without prior request and hedid not keep it for an unreasonable time. The browser software had, effectively,sent the images to Simon – he had not requested them and, because he did notknow they were even there, the question of not keeping them longer thanreasonable did not arise.

The Decision and its Impact

The court rejected both these submissions and found Simon guilty ofpossession. Contrary to good practice the court did not indicate which of thethree scenarios posited by the prosecution was the one they accepted.

The court’s decision does not necessarily have a wide impact since it has noprecedent value. It would be perfectly proper, although a little bizarre, foranother court hearing the same facts to reach an opposite conclusion.

What the decision does do however is to give the green light to other similarprosecutions. The success in this case may undermine any hesitation in bringingsimilar cases in the future.

To my mind this is a disturbing development – what may be beingcriminalised is mere looking, browsing or curiosity. Another disturbing aspectis that there does not appear to be any acknowledgement of the sometimesanarchic nature of the Net. A particular hypertext link may not give you anyidea of the true nature of the site that you consequently visit. Even if youwere promptly to leave a site devoted to child pornography in disgust then,according to this judgment, you would nevertheless have committed an offence.

The concept that a picture comes into your possession by appearing on yourmonitor is also worrying in its far-reaching implications. What of TV pictures– are you ‘in possession’ of those simply because they appear on your TVscreen?

The potentially wide impact of the case was acknowledged by one of theprosecution’s technical witnesses who stated quite candidly that he did notthink that Simon had done anything wrong and felt that the whole prosecution hadbeen brought because of the misinformation given by a PC World employee at thebeginning of the investigation, ie that the image files could only have got onto the computer by way of deliberately downloading. By the time that a betterqualified technical expert corrected this misinformation the case had taken onan awful momentum.

Lessons to Learn

The court’s decision will be the subject of an appeal to the Crown Court andthere is always a possibility that the ruling will be reversed. In the meantimethere are some practical steps that can be taken to avoid the criminalisation ofthe merely curious (particularly amongst employees with Internet access).

  1. Learn how to empty your cache and do so regularly. It may also be possible to limit the size of your browser’s cache so that WWW content is not automatically downloaded. There is obviously a downside to this – the cache is there to speed your browser’s functions up and clearing it is going to slow WWW viewing down – especially if you visit a limited number of sites regularly.
  2. Be particularly careful if you do either deliberately or accidentally encounter a site containing photographs of children. An immediate cache cleanse may be advisable.
  3. Take care over who you select to carry out any repairs to your machine and cache cleanse before submitting it for repair.

There are of course two steps to becoming embroiled in the criminal justicesystem – the commission of the relevant act and, more significantly, thediscovery of that act. It may be felt that the risk of discovery of what is,either accidentally or deliberately, on your personal computer is slight. Theconsequences of such a discovery, however, are potentially severe. In Simon’scase, even if he had been acquitted, his PC would have been out of hispossession for over a year – with no possibility of compensation. Theconsequences of such a loss to a small business could easily be disastrous.

Possessing Indecent Photographs

Most criminal legislation regulating indecent or obscene material strikes atits manufacture, importation or distribution. In general terms it is not anoffence simply to own obscene or indecent material. The one exception to thisgeneral principle is if the material is in the form of photographs (or videos),is indecent and involves children (people under 16).

Section 160 of the Criminal Justice Act provides:

  1. It is an offence for a person to have any indecent photograph or pseudo-photograph of a child in his possession.
  2. Where a person is charged with an offence under subsection (1) above, it shall be a defence for him to prove –

    (a) that he had a legitimate reason for having the photograph or pseudo-photograph in his possession; or
    (b) that he had not himself seen the photograph or pseudo-photograph and did not know, or have any cause to suspect, it to be indecent; or
    (c) that the photograph or pseudo-photograph was sent to him without any prior request made by him or on his behalf and that he did not keep it for an unreasonable time.

A ‘pseudo photograph’ is one created by image manipulation software sothat the overall appearance of any figure is that of a child. Photographs aredefined to include data held on a computer that can be resolved into an image.