telephone number or email address. Complex queries combine a number of
criteria, which may include weaker selectors but which in combination aim to
reduce the odds of a false positive. Communications that match the chosen
criteria are automatically retained, and all other communications are
automatically discarded. The retained communications are available to analysts
for possible examination.
2.18.
The application of these queries may still leave too many items for analysts to
examine, so GCHQ must then carry out a triage process to determine which will
be of most use. This triage process means that the vast majority of all the items
collected are never looked at by analysts. Even where communications are
known to relate to specific targets, GCHQ does not have the resources to
examine them all. Analysts use their experience and judgement to decide which
of the results returned by their queries are most likely to be of intelligence value
and will examine only these.
The two major processes
2.19.
A description is given in the 2015 ISC report (paras 61-73), of two major and
distinct processes that apply to interception under bulk warrants. Those
processes are identified in more detail in the closed version of the report, and I
have been briefed on each of them. In summary:
(a) The “strong selector” process (2015 ISC report, paras 61-64) operates on
the bearers that GCHQ has chosen to access. As the internet traffic flows
along those chosen bearers, the system compares the communications
against a list of strong selectors in near real-time. Any communications which
match the selectors are automatically collected and all other communications
are automatically discarded. The nature of the global internet means that the
route a particular communication will take cannot be predicted and a single
communication is broken down into packets which can take different routes.
In order to identify and reconstruct the wanted communications of subjects of
intelligence interest, GCHQ’s processing relies on accessing the “related
communications data” (secondary data) in the bearer.
A copy of all the communications on a bearer has to be held for a short
period in order to allow the strong selectors to be applied to those
communications. This process accordingly requires a bulk warrant under the
Bill. However, in the opinion of the ISC, “while this process has been
described as bulk interception because of the numbers of communications it
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