A new case highlights the difficulties where equipment and data is seized, the data is copied and the equipment returned. How can unused data be returned and how much effort should be applied to identifying the material to be returned?
In a judicial review, Business Energy Solutions Ltd & Anor v Crown Court at Preston & Anor  EWHC 1534 (Admin), the Divisional Court had to deal with novel issues about the duties of authorities who, pursuant to lawfully obtained warrants, seize computers and other electronic devices containing data which the authority then copies and retains.
The case concerned 53 terabytes seized in an exercise conducted under the Criminal Justice and Police Act 2001 when the Cheshire West and Chester Trading Standards were investigating an alleged fraud. The files included many audio files of recorded telephone conversations. Application was made under s 59 of the CJPA 2001 for return of physical property, hard copy documents and data stored and backed-up on the Trading Standards’ systems. The judge refused to make any direction about the copied data and that refusal was the subject of the judicial review.
Mr Justice Green gave the judgment of the Divisional Court, with which Bean LJ agreed. Green J pointed out that ‘return’ was not really possible and that ‘the data could be deleted but deletion is not, ordinarily, encompassed within the concept of "return"’. If the duty to return in the CJPA 2001 applies only to the physical items seized then the seizing authority is under no additional obligation to fillet the data it has subsequently copied to ensure that it is consistent with the warrant and to return the residue. But the CJPA 2001 recognises that the exercise of a power of search and seizure is a serious intrusion into private freedoms and rights and should be strictly circumscribed by the law and that is undermined by a limited reading even if retention of copied data causes no additional harm and raises ‘a far more muted public interest’.
Another issue concerned the scope of the exception to the duty to return where return was not reasonably practicable. Was ‘practicable’ based upon physical or technical capability, on the one hand, or practical capability on the other hand.
On the first issue, Green J concluded (at ), not without difficulty, that:
"return" may be construed as including within it the idea that no trace or residue of the returned property is to be left with the authority who is returning it. As such the only way in which copied data can be returned is by (a) restoration of the device in which the data is stored and (b) destruction of the copy (the trace). True it is that "return" does not naturally or easily also embrace destruction. But, nonetheless, this construction accords with Parliament's intent and achieves the "practical justice" .
The second issue was more easily dealt with. Green J pointed out that there were said to be in excess of 200 million documents and about 770,000 sound recordings. The suggestion that Trading Standards should go through each item (using such software searching facilities as it has) and filter out and then chronicle and describe and justify any document not strictly within the scope of the warrant, regardless of practical utility, the time to be taken and the costs entailed was unappealing:
‘In my view Parliament did not, when it so liberally sprinkled the expression "reasonable practicability" throughout the relevant provisions of the CJPA 2001, intend to countenance consequences such as these; rather the reverse.’
The full judgment on BAILII is here.