Related Rule
United Kingdom of Great Britain and Northern Ireland
Practice Relating to Rule 65. Perfidy
Section F. Simulation of protected status by using the distinctive emblems of the Geneva Conventions
The UK Military Manual (1958) states: “Abuse of the distinctive sign for the purpose of offensive military action is a violation both of [the 1949 Geneva Convention I], and of the laws of war in general.” 
United Kingdom, The Law of War on Land being Part III of the Manual of Military Law, The War Office, HMSO, 1958, § 379.
The UK LOAC Pamphlet (1981) states that the “feigning of non-combatant status” is an example of treachery. 
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 4, p. 12, § 2(a).
The Pamphlet specifies that “medical personnel, chaplains and civilians accompanying the armed forces are non-combatants”. 
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 3, p. 10, § 8(a).
The UK LOAC Manual (2004) states: “The wrongful use of a distinctive emblem may constitute perfidy and thus a war crime.” 
United Kingdom, The Manual of the Law of Armed Conflict, Ministry of Defence, 1 July 2004, § 7.24.1.
In its chapter relating to the wounded and sick, the manual states: “The improper use of medical units to kill, injure or capture the enemy amounts to the war crime of perfidy.” 
United Kingdom, The Manual of the Law of Armed Conflict, Ministry of Defence, 1 July 2004, § 7.13.
In its chapter on enforcement of the law of armed conflict, the manual notes:
Additional Protocol I extends the definition of grave breaches to include the following:
b. any of the following acts, when committed wilfully, in violation of the relevant provisions of the protocol, and causing death or serious injury to body or health:
(6) the perfidious use of the distinctive emblem of the red cross, red crescent or of other protective signs recognized by the Conventions or the Protocol. 
United Kingdom, The Manual of the Law of Armed Conflict, Ministry of Defence, 1 July 2004, § 16.25.
The UK Geneva Conventions Act (1957), as amended in 1995, punishes “any person, whatever his nationality, who, whether in or outside the United Kingdom, commits, or aids, abets or procures the commission by any other person of, a grave breach of … [the 1977 Additional Protocol I]”. 
United Kingdom, Geneva Conventions Act, 1957, as amended in 1995, Section 1(1).
Under the UK ICC Act (2001), it is a punishable offence to commit a war crime as defined in Article 8(2)(b)(vii) 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).