Соответствующая норма
United Kingdom of Great Britain and Northern Ireland
Practice Relating to Rule 142. Instruction in International Humanitarian Law within Armed Forces
Section B. Obligation of commanders to instruct the armed forces under their command
The UK LOAC Manual (2004) states:
Whilst ignorance of the law is not generally accepted as a defence, the first step to enforcement of the law of armed conflict must be to ensure as wide a knowledge of its terms as possible both within the armed forces and outside. 
United Kingdom, The Manual of the Law of Armed Conflict, Ministry of Defence, 1 July 2004, § 16.2.1.
The manual further states:
Parties to a conflict are obliged to instruct military commanders to prevent breaches of the law of armed conflict and ensure that their subordinates know of their obligations under that law. This provision is based on the principle that an effective disciplinary system to prevent breaches is the best way of ensuring compliance with the law of armed conflict. 
United Kingdom, The Manual of the Law of Armed Conflict, Ministry of Defence, 1 July 2004, § 16.38.