Related Rule
United Kingdom of Great Britain and Northern Ireland
Practice Relating to Rule 40. Respect for Cultural Property
The UK Military Manual (1958) provides:
611. Property belonging to local, that is, provincial, county, municipal and parochial, authorities, … as well as the property of institutions dedicated to public worship, charity, education, science and art – such as churches, chapels, synagogues, mosques, almshouses, hospitals, schools, museums, libraries, and the like – even when state property, must be treated as private property. Troops, sick and wounded, horses, and stores may therefore be housed in buildings of that nature, but such use is justified only by military necessity. Any seizure or destruction of, or wilful damage to, the property of such institutions, or to historic monuments or works of science and art, is forbidden, as is, generally, any destruction of property which is not required by imperative military necessity. Thus, it would not be improper to place sick and wounded in a church if no accommodation could immediately be found elsewhere, but a consecrated building should not be used for the purpose of barracks, stables, or stores, unless it is absolutely necessary … In 1870, the German occupation authorities housed 9,000 French prisoners of war in the Cathedral of Orleans.
613. Other movable public property, not susceptible of use for military operations, as well as that belonging to the institutions mentioned above, which is to be treated as private property, must be respected and cannot be appropriated, for instance, crown jewels, pictures, collections of works of art, and archives. However, papers connected with the war may be seized, even when forming part of archives. 
United Kingdom, The Law of War on Land being Part III of the Manual of Military Law, The War Office, HMSO, 1958, § 611 and footnote 4 and § 613.
With regard to the 1954 Hague Convention for the Protection of Cultural Property, the UK LOAC Manual (2004) states: “The detailed rules of the Convention do not apply to states not party to it, but the general principles of immunity of cultural property … do apply to those states.” 
United Kingdom, The Manual of the Law of Armed Conflict, Ministry of Defence, 1 July 2004, p. 71, fn. 114.
The manual further states:
States must avoid using cultural property for military purposes, must not direct hostilities against it, and must protect it from theft, misappropriation, vandalism, requisitioning, or reprisals. Occupying forces also have a duty to safeguard and preserve cultural property. 
United Kingdom, The Manual of the Law of Armed Conflict, Ministry of Defence, 1 July 2004, § 5.26.3.
In its chapter on internal armed conflict, the manual states: “[T]he law also prohibits … the stealing, misappropriating, confiscation of or wilful damage to cultural property”. 
United Kingdom, The Manual of the Law of Armed Conflict, Ministry of Defence, 1 July 2004, § 15.18.