CHAPTER 9: LAW ENFORCEMENT
9.29.
These requirements have not changed substantially since 2012, when the
Communications Data Bill was proposed. But I was told that law enforcement has an
improved understanding of how difficult it can be to achieve them, and of the technical
issues involved. It has recognised, in particular, that in order to maintain efficacy in a
digital world, the approach in any new law has so far as possible to be flexible and
pragmatic rather than prescriptive.
9.30.
Law enforcement argues that communications data provision is much less intrusive
than:
(a)
other surveillance methods (such as interception, directed surveillance
intrusive surveillance and the use of CHIS); and
(b)
evidential powers under PACE of search, seizure and interrogation.
All of these might only result in obtaining the same level of understanding about a
suspect and those involved in a crime. Use of communications data can build a case
for using a more intrusive measure, or deliver the information that makes other
measures unnecessary. It can, and does, exonerate innocent people without them
needing to know that they were ever under suspicion. Its marginal cost is low; it can
be started, changed and stopped easily; it involves a low risk of compromising an
investigation by being discovered by the suspects; and it is able to be used much
more widely than other forms of surveillance.
9.31.
The phrase “digital witness” sums up the approach of law enforcement to the use of
their powers. Just as it is expected practice for the police to seek the human witnesses
to any event that they are investigating, so they argue that they would be failing in
their duty were they not to seek the digital evidence that relates to a crime or other
allegation. For example, in a recent case of serial stranger rape presented on the
BBC Crimewatch programme, the crimes took place in locations where there was no
CCTV and away from residential areas. A key line of enquiry was to consider CD and
digital options (including traffic data) to locate the victim, potential witnesses and
possible suspects.
9.32.
Communications data has long been an essential part of many prosecutions: there
can have been few organised crime cases in which phone logs were not adduced in
order to establish a pattern of communications between conspirators. Nor, even, is
the ability to trace the location from which a call was made entirely novel: fixed lines
have always been in known locations. The NCA and police see their current powers
as, in large part, a translation of that well-established resource into the current age.
Indeed they fear its dilution, as explained below.
Capabilities: interception
9.33.
The capability to intercept communications is uncontroversial. But the point was made
to me by SO15, and to a lesser extent by the NCA, that current warrantry requirements
were very inflexible: “so many pieces of paper on the same target: different routes,
different authorisation levels, not much flexibility of timescale”. There was support for
greater use of dual warrants, or thematic warrants, or warrants more focussed on the
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