HC Deb 10 March 1980 vol 980 c399W
Mr. Meacher

asked the Secretary of State for the Home Department what is the legal authority under which the Post Office and the police, respectively, with or without the consent of his Department, intercept and censor private mail.

Mr. Whitelaw

The interception of postal and telephone communications is carried out only by the Post Office and then only on the authority of warrants signed by the Secretary of State. The police, who have neither the authority nor the means to intercept communications themselves, must apply to me for a warrant in accordance with the criteria and procedures set out in the Birkett report (Cmnd. 283). No question of censorship arises whether by the Post Office or by the police.