(1) This section applies to a member of the staff of the relevant Director if -
(a) the member is to exercise a function as a member of that staff under, or in relation to, Part 5 or 8; and
(b) it is necessary or expedient for the purpose of exercising that function for the member of staff to identify himself by name.
(2) The relevant Director may direct that such a member of staff may for that purpose identify himself by means of a pseudonym.
(3) For the purposes of any proceedings or application under this Act, a certificate signed by the relevant Director which sufficiently identifies the member of staff by reference to the pseudonym is conclusive evidence that that member of staff is authorised to use the pseudonym.
(4) In any proceedings or application under this Act a member of the staff of the relevant Director in respect of whom a direction under this section is in force must not be asked (and if asked is not required to answer) any question which is likely to reveal his true i
…