details. This enabled MI5 to work with law enforcement colleagues to build a strategy to
prevent any attempted travel and rapidly to focus investigative effort to build coverage of
activities of national security concern.
Without access to BPDs, MI5 might have tried to identify fully each of the hundreds of
contacts of the known extremist. However, this approach would have involved intrusion
into hundreds of individuals of no intelligence interest, and might not have identified the
individual prior to travel. A further alternative, that of interception of the known extremist’s
phone, would equally have been more intrusive, might have taken more time (including
the time needed to obtain a warrant) than MI5 believed to be available, and would not
necessarily have identified the traveller.
Case study A11/10
MI5
BPDs and bulk acquisition data
Identify
Counter-terrorism
Summarised in the Operational Case
In 2014 MI5 received intelligence that an unnamed member of Al Qaeda was suspected
of facilitating suicide bombers in the UK. The intelligence contained only one identifier
for the person (but not a name). Using BPDs, a strong candidate for the individual was
identified. During the course of this analysis, less intrusive means of identifying the
individual were explored but these did not assist in identification. At this point, more
intrusive techniques were deployed to provide positive confirmation of identity. These
techniques led MI5 to conclude that the individual did not in fact pose a threat to national
security. MI5 was then able to re-focus scarce resources towards other targets.
Case study A11/11
MI5
Identify
Counter-terrorism
Summarised in the Operational Case
During the 2012 London Olympics, interrogation of bulk personal data was used to
establish whether any of the individuals who might have had access to venues had links
with subjects of intelligence interest, and therefore might pose a threat. MI5 identified a
number of such individuals who could potentially have posed a threat, and was able to
take action further to investigate and manage the risk. The Review team saw material
which showed that analysis of BPDs enabled MI5 rapidly to assess and rule out
individuals initially thought to pose a potential threat, enabling it to focus more intrusive
resources on the individuals of greatest concern. Access to BPDs enabled MI5 to draw
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