58.—(1) This regulation applies where—
(a)a person in the United Kingdom has lawful authority to intercept telecommunications for the purposes of carrying out an investigative measure;
(b)it appears to that person that the communication address of the subject of the interception is being used on the territory of a participating State, and
(c)no technical assistance from that State is needed to carry out the interception.
(2) The person must notify the participating State of the interception—
(a)prior to the interception taking place, where the person knows that the subject is or will be on the territory of the participating State;
(b)in any other case, immediately after the person becomes aware that the subject of the interception is or has been during the period to which the interception relates, on the territory of the participating State.
(3) Notification under paragraph (2) must—
(a)be given using the form set out at Annex C to the Directive, and
(b)be accompanied by a translation into the language notified by the participating State under Article 33(1)(b) of the Directive (if that language is not English).