This work created by the United Kingdom Government is in the public domain.

This is because it is one of the following:

1. It is a photograph taken prior to 1 June 1957; or
2. It was published prior to 1974; or
3. It is an artistic work other than a photograph or engraving (e.g. a painting) which was created prior to 1974.

HMSO has declared that the expiry of Crown Copyrights applies worldwide (ref: HMSO Email Reply)
More information.

See also Copyright and Crown copyright artistic works.

This work is in the public domain in the U.S. because it is an edict of a government, local or foreign. See § 313.6(C)(2) of the Compendium of U.S. Copyright Office Practices, 3rd ed. 2014 (Compendium (Third)). Such documents include "legislative enactments, judicial decisions, administrative rulings, public ordinances, or similar types of official legal materials." These do not include works first published by the United Nations or any of its specialized agencies, or by the Organization of American States. See Compendium (Third) § 313.6(C)(2) and 17 U.S.C. § 104(b)(5).

A non-American governmental edict may still be copyrighted outside the U.S. Similarly, the above U.S. Copyright Office Practice does not prevent U.S. states or localities from holding copyright abroad, depending on foreign copyright laws and regulations.