Related Rule
United Kingdom of Great Britain and Northern Ireland
Practice Relating to Rule 53. Starvation as a Method of Warfare
The UK LOAC Pamphlet (1981) provides: “It is forbidden … to starve civilians as a method of warfare.” 
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(f).
The UK LOAC Manual (2004) states: “Starvation of civilians as a method of warfare is prohibited.” 
United Kingdom, The Manual of the Law of Armed Conflict, Ministry of Defence, 1 July 2004, § 5.27.
With regard to internal armed conflict, the manual provides:
15.19. Starvation of civilians as a method of warfare is prohibited.
15.19.1. The right to life is a non-derogable human right. Violence to the life and person of civilians is prohibited, whatever method is adopted to achieve it. It follows that the destruction of crops, foodstuffs and water sources, to such an extent that starvation is likely to follow, is also prohibited. The same applies to sieges, blockades, embargoes, or the blocking of relief supplies with the intention of causing starvation. 
United Kingdom, The Manual of the Law of Armed Conflict, Ministry of Defence, 1 July 2004, §§ 15.19–15.19.1.
Under the UK ICC Act (2001), it is a punishable offence to commit a war crime as defined in Article 8(2)(b)(xxv) 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 1990, in the UN Sanctions Committee on Iraq, the United Kingdom considered that “no one favoured allowing the inhabitants of Kuwait and Iraq to starve”. 
United Kingdom, Statement before the UN Security Council Committee Established by Resolution 661 (1990) concerning the Situation between Iraq and Kuwait, UN Doc. S/AC.25/SR.5, 12 September 1990, p. 5.
According to the Report on UK Practice, the United Kingdom supports the protection of civilians against starvation and the condemnation of starvation of civilians as a tactic in armed conflict. 
Report on UK Practice, 1997, Chapter 4.1.
The UK LOAC Manual (2004) states:
5.34. The principles of the law of armed conflict, particularly the rules relating to attacks, apply equally to situations of siege or encirclement.
5.34.2. Encirclement poses problems for the attacking commander if there are civilians in the encircled area, especially if the encircled area is, or contains, a town which is inhabited by civilians but is defended by enemy armed forces. In any bombardment, the normal rules on precautions in attack apply. So do the rules preventing starvation of the civilian population as a method of warfare or those protecting supplies indispensable for the survival of the civilian population. There is also an obligation to allow essential relief supplies through to the civilian population. 
United Kingdom, The Manual of the Law of Armed Conflict, Ministry of Defence, 1 July 2004, §§ 5.34. and 5.34.2.
With regard to internal armed conflict, the manual states:
15.19. Starvation of civilians as a method of warfare is prohibited.
15.19.1. The right to life is a non-derogable human right. Violence to the life and person of civilians is prohibited, whatever method is adopted to achieve it. It follows that the destruction of crops, foodstuffs and water sources, to such an extent that starvation is likely to follow, is also prohibited. The same applies to sieges, blockades, embargoes, or the blocking of relief supplies with the intention of causing starvation. 
United Kingdom, The Manual of the Law of Armed Conflict, Ministry of Defence, 1 July 2004, §§ 15.19–15.19.1.
The UK LOAC Manual (2004) states:
The declaration or establishment of a blockade is prohibited if:
a. it is intended to starve the civilian population or deny it objects essential for its survival; or
b. the damage to the civilian population is, or may be expected to be, excessive in relation to the concrete and direct military advantage anticipated from the blockade. 
United Kingdom, The Manual of the Law of Armed Conflict, Ministry of Defence, 1 July 2004, § 13.74.
With regard to internal armed conflict, the manual states:
15.19. Starvation of civilians as a method of warfare is prohibited.
15.19.1. The right to life is a non-derogable human right. Violence to the life and person of civilians is prohibited, whatever method is adopted to achieve it. It follows that the destruction of crops, foodstuffs and water sources, to such an extent that starvation is likely to follow, is also prohibited. The same applies to sieges, blockades, embargoes, or the blocking of relief supplies with the intention of causing starvation. 
United Kingdom, The Manual of the Law of Armed Conflict, Ministry of Defence, 1 July 2004, §§ 15.19–15.19.1.