القاعدة ذات الصلة
United Kingdom of Great Britain and Northern Ireland
Practice Relating to Rule 37. Open Towns and Non-Defended Localities
Section C. Attacks on open towns and non-defended localities
The UK Military Manual (1958) states, with reference to Article 25 of the 1907 Hague Regulations, that the distinction between “defended” and “undefended” localities still exists and is not invalidated by the considerable destructive power of modern artillery and guided missiles. It clearly states the prohibition of any attack against undefended localities. 
United Kingdom, The Law of War on Land being Part III of the Manual of Military Law, The War Office, HMSO, 1958, § 290.
The manual further states: “In addition to the ‘grave breaches’ of the 1949 [Geneva] Conventions … the following are examples of punishable violations of the laws of war, or war crimes: … (c) firing on undefended localities”. 
United Kingdom, The Law of War on Land being Part III of the Manual of Military Law, The War Office, HMSO, 1958, § 626(c).
The UK LOAC Pamphlet (1981) states that it is forbidden “to attack or bombard undefended towns, villages, dwellings or buildings”. 
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. 14, § 5(c).
The UK LOAC Manual (2004) states:
“The attack or bombardment, by whatever means, of towns, villages, dwellings, or buildings which are undefended is prohibited.” The reason for this rule is that there is no military need to attack a place that is not being defended. It can simply be occupied without resistance or bypassed.
“It is prohibited for the Parties to the conflict to attack, by any means whatsoever, non-defended localities.” 
United Kingdom, The Manual of the Law of Armed Conflict, Ministry of Defence, 1 July 2004, § 5.38; see also § 12.26 (air operations).
With regard to internal armed conflict, the manual states:
15.25. It is prohibited to attack or bombard, by whatever means, towns, villages, dwellings, or buildings that are undefended.
15.25.1. If a town, village, or building is undefended and can be occupied without resistance, there is no need to attack it and it is prohibited to do so. It is also prohibited to attack buildings unless they are military objectives. Undefended towns and villages that cannot be occupied because they are behind enemy lines or are in areas controlled by enemy forces may also not be attacked as such. Attacks against specific military objectives in those towns and villages are permitted, though precautions must be taken to minimize incidental loss or damage.
15.25.2. The other rules on protective zones applicable in international armed conflicts may be applied by analogy to internal armed conflicts. 
United Kingdom, The Manual of the Law of Armed Conflict, Ministry of Defence, 1 July 2004, §§ 15.25–15.25.2.
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:
(4) making non-defended localities and demilitarized zones the object of attack. 
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)(v) 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).