BIG BROTHER WATCH AND OTHERS v. THE UNITED KINGDOM JUDGMENT
3. GENERAL RULES ON INTERCEPTION WITH A WARRANT
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3.7. The following elements of proportionality should therefore be considered:
Balancing the size and scope of the proposed interference against what is
sought to be achieved;
Explaining how and why the methods to be adopted will cause the least
possible intrusion on the subject and others;
Considering whether the activity is an appropriate use of the legislation and
a reasonable way, having considered all reasonable alternatives, of
obtaining the necessary result;
Evidencing, as far as reasonably practicable, what other methods have been
considered and were either not implemented or have been employed but
which are assessed as insufficient to fulfil operational objectives without
the addition of the intercept material sought.
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Duration of interception warrants
3.18. Interception warrants issued on serious crime grounds are valid for an initial
period of three months. Interception warrants issued on national security/economic
well-being of the UK grounds are valid for an initial period of six months. A warrant
issued under the urgency procedure (on any grounds) is valid for five working days
following the date of issue unless renewed by the Secretary of State.
3.19. Upon renewal, warrants issued on serious crime grounds are valid for a
further period of three months. Warrants renewed on national security/economic
well-being of the UK grounds are valid for a further period of six months. These dates
run from the date on the renewal instrument.
3.20. Where modifications to an interception warrant are made, the warrant expiry
date remains unchanged. However, where the modification takes place under the
urgency provisions, the modification instrument expires after five working days
following the date of issue, unless it is renewed in line with the routine procedure.
3.21. Where a change in circumstance leads the intercepting agency to consider it
no longer necessary, proportionate or practicable for a warrant to be in force, the
agency must make a recommendation to the Secretary of State that it should be
cancelled with immediate effect.
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4. SPECIAL RULES ON INTERCEPTION WITH A WARRANT
Collateral intrusion
4.1. Consideration should be given to any interference with the privacy of
individuals who are not the subject of the intended interception, especially where
communications relating to religious, medical, journalistic or legally privileged
material may be involved, or where communications between a Member of Parliament
and another person on constituency business may be involved or communications
between a Member of Parliament and a whistle-blower. An application for an
interception warrant should state whether the interception is likely to give rise to a
degree of collateral infringement of privacy. A person applying for an interception
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