46.Where an application is made for an intrusive surveillance authorisation and the case is urgent but it is not reasonably practicable for the application to be considered by a chief constable in the police force or his designated deputy, an authorisation may be granted by a person entitled to act in his/her absence. Subsection (4) details the officers entitled so to act and subsection (5) sets down those officers entitled to act as “designated deputies”.
47.Subsection (3) provides that in the case where a person considers an application for an authorisation for the carrying out of intrusive surveillance where the case is urgent, the person concerned shall have the same power to grant an authorisation as the person for whom he is entitled to act. The person concerned would be a person who is entitled under section 12(4) to act for the chief constable.
Commentary on Sections Authorisation of surveillance and human intelligence sources Section 12:  Grant of authorisations in cases of emergency