The power of the Parish Council to create a historical records archive comes from:
Local Government (Records) Act 1962
Section 1: Power to promote adequate use of records.
(1) A local authority may do all such things as appear to it necessary or expedient for enabling adequate use to be made of records under its control, and in relation to such records may in particular—
(a) make provision for enabling persons, with or without charge and subject to such conditions as the authority may determine, to inspect the records and to make or obtain copies thereof;
(b) prepare, or procure or assist in the preparation of, indexes and guides to and calendars and summaries of the records;
Section 2: Acquisition and deposit of records.
(1) A local authority to which this subsection applies may—
(a) by agreement acquire by way of purchase records which, or (in the case of a collection) the majority of which, appear to the authority to be of local interest;
(b) accept the gift of records which, or (in the case of a collection) the majority of which, appear to the authority to be of general or local interest.