Related Rule
United Kingdom of Great Britain and Northern Ireland
Practice Relating to Rule 138. The Elderly, Disabled and Infirm
Section B. The disabled and infirm
The UK Military Manual (1958) provides:
Special protection and respect must be given to … the infirm …
The belligerents shall endeavour to conclude local agreements for the removal from besieged or encircled areas of … [the] infirm …
Convoys of vehicles or hospital trains on land, and specially provided vessels at sea, conveying … the infirm … must be protected and respected in the same way as civilian hospitals. 
United Kingdom, The Law of War on Land being Part III of the Manual of Military Law, The War Office, HMSO, 1958, §§ 28, 29, 32 and 33.
The UK Government Strategy on the Protection of Civilians in Armed Conflict (2010) states: “Specific population groups such as … the disabled benefit from additional protection provided for in specific conventions.” 
United Kingdom, Foreign and Commonwealth Office, Government Strategy on the Protection of Civilians in Armed Conflict, March 2010, p. 4.