Concerned prison rules permitting the INTERCEPTION OF LETTERS to and from a prisoner, including correspondence with his lawyers. Interfered with constitutional right.
The interference could only be authorised by express words in the statute or by necessary implication. That necessary implication could only arise where the purpose of Parliament could not be achieved without the right being infringed or the function of the public body could not be discharged without it. Even if this was satisfied, the right could still not be infringed to any greater extent than was necessary in order to achieve the statutory objective. The Court of Appeal in Leech accepted that, by necessary implication, the Prison Act 1952 authorised some screening of correspondence passing between a prisoner and a solicitor. But the prison rules, made under the authority of that statute, were too wide in permitting all letters to and from a prisoner to be read.
The authorised intrusion had to be the minimum necessary to ensure that the correspondence was in truth bona fide legal correspondence.