Section 85 does not prevent an officer from taking any action for the purposes of an investigation if—
the action is necessary as a matter of urgency to prevent the investigation being substantially and irrevocably prejudiced,
the requirements of subsection (2) are met, and
either—
the action is authorised under subsection (3), or
the requirements of subsection (5) are met.
The requirements of this subsection are met if—
there has been no undue delay in applying for consent under section 85(2),
that consent has not been refused, and
taking into account the urgency of the situation, it is not reasonably practicable to obtain that consent before taking the action.
An officer of the rank of superintendent or above may authorise the action if—
he is satisfied that new evidence has been obtained which would be relevant to an application under section 76(1) or (2) in respect of the qualifying offence to which the investigation relates, or
he has reasonable grounds for believing that such new evidence is likely to be obtained as a result of the investigation.
An authorisation under subsection (3) must—
if reasonably practicable, be given in writing;
otherwise, be recorded in writing by the officer giving it as soon as is reasonably practicable.
The requirements of this subsection are met if—
there has been no undue delay in applying for authorisation under subsection (3),
that authorisation has not been refused, and
taking into account the urgency of the situation, it is not reasonably practicable to obtain that authorisation before taking the action.
Where the requirements of subsection (5) are met, the action is nevertheless to be treated as having been unlawful unless, as soon as reasonably practicable after the action is taken, an officer of the rank of superintendent or above certifies in writing that he is satisfied that, when the action was taken—
new evidence had been obtained which would be relevant to an application under section 76(1) or (2) in respect of the qualifying offence to which the investigation relates, or
the officer who took the action had reasonable grounds for believing that such new evidence was likely to be obtained as a result of the investigation.