Norma relacionada
United Kingdom of Great Britain and Northern Ireland
Practice Relating to Rule 65. Perfidy
Section E. Simulation of an intention to negotiate under the white flag of truce
The UK Military Manual (1958), in connection with the requirements for being granted the status of combatant, notes in particular that irregular troops “should have been warned against the employment of treachery [and] improper conduct towards flags of truce”. 
United Kingdom, The Law of War on Land being Part III of the Manual of Military Law, The War Office, HMSO, 1958, § 95.
The manual considers it a legitimate ruse “to utilise an informal suspension of arms for the purpose of collecting wounded and dead … to execute movements unseen by the enemy”. For instance, it notes an incident during the Russo-Japanese War of 1905, in which a group of Russians under the protection of the white flag and the red cross emblem advanced towards the Japanese army and asked for a suspension of arms to collect the wounded and the dead. It then used the occasion to withdraw completely. 
United Kingdom, The Law of War on Land being Part III of the Manual of Military Law, The War Office, HMSO, 1958, § 319, including footnote 1.
The manual condemns as unlawful the use of a “white flag for the purpose of making the enemy believe that a parlementaire is about to be sent when there is no such intention, and to carry out operations under the protection granted by the enemy to the pretended flag of truce”. 
United Kingdom, The Law of War on Land being Part III of the Manual of Military Law, The War Office, HMSO, 1958, § 416.
The manual states: “Abuse of a flag of truce constitutes gross perfidy and entitles the injured party to take reprisals or to try the offenders if captured.” 
United Kingdom, The Law of War on Land being Part III of the Manual of Military Law, The War Office, HMSO, 1958, § 417.
The UK LOAC Pamphlet (1981) provides: “Abuse of the white flag is 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, Annex A, p. 46, § 5.
The UK LOAC Manual (2004) states:
It is forbidden to make improper use of a flag of truce. Thus, a feigned intention to negotiate or surrender with the intention of using the white flag as cover for the collection of information might amount to the war crime of perfidy whatever the consequences. It would amount to a grave breach of Additional Protocol I if it resulted in death or serious injury. A parlementaire who abuses his position in this way can be taken as a prisoner of war and tried. 
United Kingdom, The Manual of the Law of Armed Conflict, Ministry of Defence, 1 July 2004, § 10.10.1.
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).
A training video on IHL produced by the UK Ministry of Defence emphasizes that it constitutes treachery to fire under the cover of protection of the flag of truce. 
United Kingdom, Ministry of Defence, Training Video: The Geneva Conventions, 1986, Report on UK Practice, 1997, Chapter 2.2.