British Telecommunications Act 1981

2 For the purposes of so much of section 32(1) of the [1949 c. 87.] Patents Act 1949 as provides that a patent may be revoked on the grounds that the invention, so far as claimed in any claim of the complete specification, was secretly used in the United Kingdom before the priority date of that claim, no account shall be taken of any use, on or after the appointed day, of the invention by the Corporation or a person authorised by it, in consequence of the applicant for the patent or any person from whom he derives title having communicated or disclosed the invention directly or indirectly—

(a) before 1st October 1969, to a government department or person authorised by a government department;

(b) on or after 1st October 1969, in pursuance of an agreement in the case of which rights and liabilities thereunder vested in the Post Office by virtue of the 1969 Act, to the Post Office or a person authorised by it; or

(c) on or after the appointed day, in pursuance of an agreement to which this Schedule applies, to the Corporation or a person authorised by it.