Related Rule
United Kingdom of Great Britain and Northern Ireland
Practice Relating to Rule 115. Disposal of the Dead
Section C. Cremation of bodies
The UK Military Manual (1958) states:
Bodies must not be cremated except for imperative reasons of hygiene or for motives based on the religion of the deceased. When cremation is carried out the circumstances and reasons for it must be stated in detail on the death certificate. 
United Kingdom, The Law of War on Land being Part III of the Manual of Military Law, The War Office, HMSO, 1958, § 384.
The UK LOAC Pamphlet (1981) provides: “Cremation is allowed only on religious grounds or for imperative reasons of hygiene.” 
United Kingdom, The Law of Armed Conflict, D/DAT/13/35/66, Army Code 71130 (Revised 1981), Ministry of Defence, prepared under the Direction of The Chief of the General Staff, 1981, Section 6, p. 22, § 5.
The UK LOAC Manual (2004) states:
Bodies must not be cremated except for imperative reasons of hygiene or for motives based on the religion of the deceased. When cremation is carried out, the circumstances and the reasons for it must be stated in the death certificate. The ashes must be respectfully treated and kept by the official graves registration service until properly disposed of according to the wishes of the home country. 
United Kingdom, The Manual of the Law of Armed Conflict, Ministry of Defence, 1 July 2004, § 7.35.