55.  (1) Subject to this Act, where any postal article is in the course of transmission by post, no employee of the licensee shall open it or deliver it to any person other than the addressee, or permit it to be opened or delivered to any person other than the addressee, unless he is authorised to do so by express authority in writing under the hand of the licensee:

Provided that, nothing in this Part shall preclude the examination of any postal article and the disposal of any article in accordance with the provisions of any law -

(a) relating to customs; or

(b) prohibiting or regulating the importation or exportation of any article.

(2) The licensee may, in any individual case which appears to warrant such a course of action, grant its warrant for opening or returning any specified postal article.