Report of the Independent Surveillance Review
53
to examine or read. According to the ISC, ‘This involves complex searches to draw out
communications most likely to be of greatest intelligence value and which relate to
GCHQ’s statutory functions. These searches generate an index. Only items contained
in this index can potentially be examined – all other items cannot be searched for,
examined or read’.19
3.28
At each stage, a judgement on necessity and proportionality is made. These judgements
are made not only for ethical and legal reasons, but also practical reasons, in order to
quickly focus on the most serious threats. In this way, good legal compliance and good
business practice become one and the same; as noted by the ISC, GCHQ only has the
capacity to analyse a fraction of available information, so the goal is both to be minimally
intrusive and to maximise returns, filtering data to generate the smallest number of
high-quality leads.
MI5
3.29
MI5 are a security and intelligence organisation. It is charged to act in the interests
of national security; for the purposes of preventing or detecting serious crime; and
safeguarding the economic well-being of the UK. While working under the objectives
set by the NSC, MI5 are tasked slightly differently, and is set more generic priorities by
government compared to its sister agencies. Around 65 per cent of MI5’s effort and
resources are dedicated to countering terrorism, while 10 per cent of the agency’s work
involves working with the Centre for the Protection of National Infrastructure (CPNI) in
securing physical, personnel and cyber-security in the UK. Unlike SIS and GCHQ, MI5 is
tasked to carry out national security investigations in addition to gathering intelligence.
3.30
MI5 possess significant technological capabilities, though it will seek the expertise of
GCHQ where necessary. MI5’s relationship with GCHQ has changed significantly over the
last five years, particularly given the more extensive role of Internet communications. It
is able to utilise GCHQ’s capabilities (and vice versa) with Home Office agreement.
SIS
3.31
SIS collect secret intelligence and mounts covert operations overseas in support of
British government objectives. The Panel were told that the use of intercept material,
communications data and bulk data sets is crucial to its activities. Technology has
had a fundamental impact on all aspects of the work of SIS: in identifying new
agents, communicating with agents, understanding the operational environment and
understanding the capabilities of hostile actors.
3.32
SIS needs to maintain a net technological advantage over adversaries; it recognises the
responsibilities that this confers, and the accountability and oversight mechanisms that
19. Intelligence and Security Committee of Parliament (ISC), Privacy and Security: A Modern
and Transparent Legal Framework (London: The Stationery Office, 2015), p. 112.