Related Rule
United Kingdom of Great Britain and Northern Ireland
Practice Relating to Rule 80. Booby-Traps
The UK LOAC Pamphlet (1981), under the heading “Future Developments”, considers the possibility of a treaty imposing “restrictions on the use of booby-traps”. 
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 11, p. 40, § 4(b).
The UK LOAC Manual (2004) states:
6.7. The use of booby-traps is permitted provided certain conditions are complied with. First, they must be directed against combatants and may not under any circumstances be directed against civilians. Secondly, indiscriminate use is prohibited. That means that the method used, or the circumstances, must be such that there is a reasonable prospect that only combatants will become victims of the booby-traps and that the risk to civilians does not outweigh the military advantage of laying booby-traps. Care has to be taken to ensure that civilians do not become the unwitting victims of booby-traps. So, thirdly, feasible precautions must be taken to protect civilians from their effects. Feasible precautions are those which “are practicable or practically possible taking into account all circumstances ruling at the time, including humanitarian and military considerations”. Further prohibitions of, or restriction on the use of, booby-traps are set out in sub-paragraphs 6.7.3. to 6.7.7.
6.7.1. A booby-trap is “any device or material which is designed, constructed or adapted to kill or injure, and which functions unexpectedly when a person disturbs or approaches an apparently harmless object or performs an apparently safe act”. For example, in the case of a booby-trapped doorway, opening the door would be an apparently safe act with respect to the door.
6.7.2. A military logistic installation that is being abandoned in a hurry during a withdrawal could be booby-trapped, but with signs to that effect posted on the perimeter of the installation as a warning to civilians not to enter it.
Prohibitions and restrictions on use of booby-traps
6.7.3. Where combat between ground forces is neither taking place nor appears imminent, booby-traps may not be used at all in populated areas unless either:
a. “they are placed on or in the close vicinity of a military objective;” or
b. “measures are taken to protect civilians from their effects, for example, the posting of warning [signs, the posting of] sentries, the issue of warnings or the provision of fences.”
6.7.4. “It is prohibited to use booby-traps in the form of apparently harmless portable objects which are specifically designed and constructed to contain explosive material”. This prohibition relates to booby-traps made to look like watches, personnel audio players, cameras and the like. This is to prevent the production of large quantities of dangerous objects that can be scattered around and picked up by civilians, especially children. It does not prohibit, subject to paragraph 6.7.5 the booby-trapping of existing items of that sort.
6.7.5. It is also prohibited in all circumstances to use booby-traps “attached to or associated with”:
a. “internationally recognized protective emblems, signs or signals”;
b. “sick, wounded or dead persons”;
c. “burial or cremation sites or graves”;
d. “medical facilities, medical equipment, medical supplies or medical transportation”;
e. “children’s toys or other portable objects or products specially designed for the feeding, health, hygiene, clothing or education of children”;
f. “food or drink”;
g. “kitchen utensils or appliances except in military establishments, military locations or military supply depots”;
h. ‘objects clearly of a religious nature’;
i. “historic monuments, works of art or places of worship which constitute the cultural or spiritual heritage of peoples”;
j. ‘animals or their carcasses.’
6.7.6. It is also prohibited in all circumstances to use any booby-trap which is designed to cause superfluous injury or unnecessary suffering. Although these would be prohibited under the guiding principle set out at the beginning of this chapter, the drafters of this provision had in mind booby-traps specifically designed to cause a cruel or lingering death, their purpose being to intimidate through terror.
6.7.7. It is further prohibited to use booby-traps which are designed to be detonated by mine detectors.
Recording
6.7.8. Recording the location of booby-traps is required. This not only protects civilians but also protects one’s own or allied troops and also enables booby-traps to be deactivated as soon as they are no longer required.
6.7.9. For details of the making of records, the use of records, the protection of United Nations forces or missions and the removal of booby-traps, see the corresponding provisions in respect of landmines in paragraph 6.14.6. 
United Kingdom, The Manual of the Law of Armed Conflict, Ministry of Defence, 1 July 2004, §§ 6.7–6.7.9.
The manual further states:
The Amended Mines Protocol [the 1996 Amended Protocol II to the Convention on Certain Conventional Weapons] contains detailed provisions on the clearance of mines and booby-traps after the cessation of active hostilities. Basically states are responsible for devices they have emplaced and for the areas under their control. There are provisions for international exchanges of information and co-operation in this respect. 
United Kingdom, The Manual of the Law of Armed Conflict, Ministry of Defence, 1 July 2004, § 6.14.10.
In its chapter on the application of the law of armed conflict during peace-support operations, the manual states:
Insofar as a party to an armed conflict is not subject to a more extensive prohibition or restriction on the use of landmines, the Mines Protocol to the United Nations Convention on Conventional Weapons [the 1980 Protocol II to the Convention on Certain Conventional Weapons] requires it to take certain steps to protect United Nations forces from mines and booby-traps. 
United Kingdom, The Manual of the Law of Armed Conflict, Ministry of Defence, 1 July 2004, § 14.14.