Related Rule
United Kingdom of Great Britain and Northern Ireland
Practice Relating to Rule 88. Non-Discrimination
Section A. General
The UK LOAC Pamphlet (1981) incorporates the provisions of common Article 3 of the 1949 Geneva Conventions. 
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 12, p. 42, § 2(a).
In its chapter on the applicability of the law of armed conflict, the UK LOAC Manual (2004) states:
… every victim of armed conflict is entitled to the protection afforded by the law. The fact that he is a national, or member of the armed forces, of any particular state or that he has particular religious convictions or political opinions is irrelevant in this context. 
United Kingdom, The Manual of the Law of Armed Conflict, Ministry of Defence, 1 July 2004, § 3.12.1.
In its chapter on the protection of civilians in the hands of a party to the conflict, the manual states:
All persons are to be treated humanely in all circumstances and “without any adverse distinction based upon race, colour, sex, language, religion or belief, political or other opinion, national or social origin, wealth, birth or other status or on any other similar criteria”. 
United Kingdom, The Manual of the Law of Armed Conflict, Ministry of Defence, 1 July 2004, § 9.3.
In its chapter on internal armed conflict, the manual restates the provisions of common Article 3 of the 1949 Geneva Conventions:
Under the terms of Common Article 3, the parties to a non-international armed conflict occurring in the territory of a party to the Conventions are obliged to apply “as a minimum”, the following provisions:
(1) Persons taking no active part in the hostilities, including members of armed forces who have laid down their arms and those placed hors de combat by sickness, wounds, detention, or any other cause, shall in all circumstances be treated humanely, without any adverse distinction founded on race, colour, religion or faith, sex, birth or wealth, or any other similar criteria. 
United Kingdom, The Manual of the Law of Armed Conflict, Ministry of Defence, 1 July 2004, § 15.4.
Furthermore, the manual provides that, in internal armed conflicts in which the 1977 Additional Protocol II is applicable, it applies “without any adverse distinction founded on race, colour, sex, language, religion or belief, political or other opinion, national or social origin, wealth, birth or other status, or on any other similar criteria” to all persons affected by the conflict. 
United Kingdom, The Manual of the Law of Armed Conflict, Ministry of Defence, 1 July 2004, § 15.36.
Under the UK ICC Act (2001), it is a punishable offence to commit a crime against humanity as defined in Article 7(1)(h) of the 1998 ICC Statute. 
United Kingdom, ICC Act, 2001, Sections 50(1) and 51(1) (England and Wales) and Section 58(1) (Northern Ireland).
In 2010, in its closing submissions to the public inquiry into the circumstances surrounding the death of Baha Mousa and the treatment of those detained with him by UK armed forces in Iraq in 2003, the UK Ministry of Defence stated regarding common Article 3 of the 1949 Geneva Conventions: “On its face this protection is restricted to armed conflicts not of an international character. However, it is understood to apply in all forms of armed conflict as part of customary international law to set out the irreducible minimum standard.” 
United Kingdom, Ministry of Defence, Closing Submissions to the Baha Mousa Public Inquiry on Modules 1–3, 25 June 2010, § 10.2, p. 10.