Related Rule
United Kingdom of Great Britain and Northern Ireland
Practice Relating to Rule 139. Respect for International Humanitarian Law
Section B. Orders and instructions to ensure respect for international humanitarian law
The UK LOAC Manual (2004) states:
States are under a general obligation to issue orders and instructions requiring compliance with the law of armed conflict and to take steps to see that those orders and instructions are observed. There is a specific provision in relation to the handling of the wounded, sick and shipwrecked, extending to a requirement to provide for unforeseen situations “in conformity with the general principles” of the Geneva Conventions 1949. These are that the wounded, sick and shipwrecked should be cared for and treated without any adverse distinction. 
United Kingdom, The Manual of the Law of Armed Conflict, Ministry of Defence, 1 July 2004, § 16.2.