HC Deb 06 February 1969 vol 777 c155W
65. Mr. Parker

asked the Postmaster-General by what authority and procedure mail is opened on his instructions, or at the request or on the recommendations of a Government Department or Minister of the Crown.

Mr. Stonehouse

The power to open mail derives from Sections 16 and 58 of the Post Office Act, 1953. Mail may be opened for Customs examination or, if it is undeliverable, to ascertain the sender's name and address. Otherwise it is opened only under warrant signed by a Secretary of State.