techniques were then put in place while the group was present; through these, MI5
obtained valuable intelligence on their connections to extremists overseas. Without bulk
acquisition data, MI5 would have had to use more targeted measures, such as increased
surveillance of members of the group. A further alternative would have been to monitor
the meeting place. However, MI5 does not believe that the intelligence could have been
obtained through these means without an unacceptable level of collateral intrusion,
including the monitoring of people completely unconnected to the targets. The
information obtained through bulk acquisition data contributed to the decision to ensure
that measures were taken to prevent the individuals from travelling abroad.
Case study A9/15
MI5
Understand
Counter-terrorism
In 2015, MI5 was monitoring an individual who was known to be involved in attack
planning in the UK, and whose mental health rendered him volatile and at risk of taking
spontaneous action. Targeted intelligence revealed that the individual had obtained a
new mobile phone. Bulk acquisition data was used to identify that phone, which was then
subjected to targeted interception. The individual was arrested while committing a
criminal offence, and was subsequently convicted.
Without bulk acquisition data, MI5 would have had to deploy more intrusive techniques in
order to identify the phone. The alternative methods were explained to the Review team.
All of these methods would have been more time-consuming, and some would have
resulted in more collateral intrusion. They would also have been less efficient, and
carried a greater risk of the correct phone not being identified. Further, had MI5 been
unable to identify the phone and intercept communications, it would have had less
certainty about the individual’s plans and the risks that he posed. The police might have
had to disrupt the individual’s plans earlier than they did, in order to protect the public,
and might have had to do so before obtaining evidence admissible in criminal
proceedings.
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