Règle correspondante
United Kingdom of Great Britain and Northern Ireland
Practice Relating to Rule 7. The Principle of Distinction between Civilian Objects and Military Objectives
Section B. Attacks against military objectives
The UK Military Manual (1958) provides:
283. Bombardment and siege of defended localities are legitimate means of warfare. …
288. In defended towns and localities modern methods of bombardment will inevitably destroy many buildings and sites which are not military objectives. Such destruction, if incidental to the bombardment of military objectives is not unlawful. For example the bombardment of a war factory area may well destroy the houses of workers living in that area. If, on the other hand, bombardment is directed solely against a non-military objective, it is unlawful. 
United Kingdom, The Law of War on Land being Part III of the Manual of Military Law, The War Office, HMSO, 1958, Articles 283 and 288.
The UK LOAC Pamphlet (1981) provides: “Military operations may only be directed against military objectives.” 
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. 13, § 4(a).
The UK LOAC Manual (2004) states: “Attacks shall be limited strictly to military objectives.” 
United Kingdom, The Manual of the Law of Armed Conflict, Ministry of Defence, 1 July 2004, § 5.4; see also §§ 12.21, 12.26 (air operations) and § 13.27 (maritime warfare).
In 1938, during a debate in the House of Commons, the UK Prime Minister Neville Chamberlain listed among rules of international law applicable to warfare on land, at sea and from the air the rule that “targets which are aimed at … must be legitimate military targets and must be capable of identification”. 
United Kingdom, House of Commons, Statement by the Prime Minister, Sir Neville Chamberlain, 21 June 1938, Hansard, Vol. 337, col. 937.
At the CDDH, the United Kingdom stated that it did not interpret the obligation in the first sentence of Article 47(2) of the draft Additional Protocol I (now Article 52(2))
as dealing with the question of incidental damage caused by attacks directed against military objectives. In its view, the purpose of the first sentence of the paragraph was to prohibit only such attacks as might be directed against non-military objectives. 
United Kingdom, Statement at the CDDH, Official Records, Vol. VI, CDDH/SR.41, 26 May 1977, p. 169, § 153.
It is reported that, during the War in the South Atlantic, both parties directed their hostile acts only against military objectives. 
Carlos Horacio Cerdá, El respeto del Derecho International Humanitario durante el Dessarollo del Conflicto Armado del Atlántico Sud, Report on the Practice of Argentina, 1997, Chapter 1.3.
In reply to questions in the House of Lords and House of Commons concerning military operations during the Gulf War in 1991, the UK Under-Secretary of State for Defence and the Minister of State for the Armed Forces stated that it was a policy of the allies to attack only military targets and facilities that sustained Iraq’s illegal occupation of Kuwait. 
United Kingdom, House of Lords, Statement by the Parliamentary Under-Secretary of State for Defence, 27 February 1991, Hansard, Vol. 526, Written Answers, col. 52; Statement by the Minister of State for the Armed Forces, 28 February 1991, Hansard, Vol. 186, Written Answers, col. 611.
A training video on IHL produced by the UK Ministry of Defence emphasizes that military operations must be directed only against military objectives. 
United Kingdom, Ministry of Defence, Training Video: The Geneva Conventions, 1986, Report on UK Practice, 1997, Chapter 1.3.
Upon ratification of the 1977 Additional Protocol I, the United Kingdom stated:
It is the understanding of the United Kingdom that … the first sentence of paragraph 2 [of Article 52] prohibits only such attacks as may be directed against non-military objectives; it does not deal with the question of collateral damage resulting from attacks directed against military objectives. 
United Kingdom, Reservations and declarations made upon ratification of the 1977 Additional Protocol I, 28 January 1998, § j.
In 2003, in reply to a written question in the House of Commons, the UK Secretary of State for Defence wrote:
The military campaign is crafted around the principle of minimum use of force. We attack only military objectives and combatants subject to the constraints of proportionality. If there is any expectation that harm will be caused to civilians, this must not be excessive when set against the direct and concrete military advantage anticipated from the attack. 
United Kingdom, House of Commons, Written answer by the Secretary of State for Defence, Hansard, 9 April 2003, Vol. 403, Written Answers, col. 297W.
The UK Government Strategy on the Protection of Civilians in Armed Conflict (2010) states: “IHL requires parties to a conflict to respect and protect civilians. In the conduct of military operations they must … only direct attacks against … military objectives.” 
United Kingdom, Foreign and Commonwealth Office, Government Strategy on the Protection of Civilians in Armed Conflict, March 2010, p. 4.