Part 4: Retention of communications data Section 91: Approval of retention notices following review under section 90
This section sets out the test that the Investigatory Powers Commissioner must apply when considering whether to approve a decision by the Secretary of State to vary a retention notice or give a notice confirming the effect of a retention notice following a review of that notice under section 90. He or she must review the conclusions the Secretary of State came to regarding the necessity and proportionality of the requirement to retain communications data. In doing so the Investigatory Powers Commissioner must apply the same principles that a court would apply on an application for judicial review. The Commissioner must review the conclusions as to necessity and proportionality with sufficient care to comply with the general privacy duties set out in section 2.
	Subsection (4) makes clear that where the Investigatory Powers Commissioner refuses to approve a decision to vary a retention notice or give a notice confirming the effect of a retention notice, he or she must set out written reasons for the refusal.