Select Committee on Constitution Fifteenth Report

Waging war: Parliament's role and responsibility



1.  Under the Royal prerogative powers, the Government can declare war and deploy armed forces to conflicts abroad without the backing or consent of Parliament. However, the Government agreed to a parliamentary vote before the Iraq war in 2003. Subsequently, there have been calls for a requirement that Government should always seek Parliament's approval when taking action in future conflicts.

2.  In 2004, the House of Commons' Public Administration Select Committee published a report on Ministers' prerogative powers, recommending that "any decision to engage in armed conflict should be approved by Parliament, if not before military action then as soon as possible afterwards".[1] The Government responded that they were "not persuaded" that replacing prerogative powers within a statutory framework would improve the present position.[2] Since then, three Private Members Bills have been brought forward in Parliament, seeking to give Parliament a greater role in the exercise of these royal prerogative powers, and several leading parliamentarians from across the political spectrum have spoken to similar effect. The primary motive has been to reinforce both the legality and the legitimacy of such action by giving Parliament a role in the decision-making process.

3.  The purpose of our inquiry has been to consider what alternatives there are to the use of the Royal prerogative power in the deployment of armed force, whether there should be a more direct role for Parliament and in particular whether Parliamentary approval should be required for any deployment of British forces outside the United Kingdom (whether or not into areas of conflict), or if there is a need for different approaches in different situations, for example in honouring commitments under international treaties or in pursuance of UN Security Council resolutions. Other important issues for consideration have been whether the Government should be required, or expected, to explain the legal justification for any decision to use force outside the United Kingdom, and whether the courts have jurisdiction to rule upon the decision to use force.



4.  The Royal prerogative derives from the constitutional settlement enshrined in the Bill of Rights 1688, which in effect transferred to Ministers certain rights which were previously the exclusive preserve of the Monarch. It did not abolish the prerogative, but allowed Parliament to take specific steps to modify, abolish or put any particular prerogative power on a statutory footing. Thus it would no longer be sufficient for the Crown (or its Ministers) to invoke the prerogative to justify its actions. It would have to show that at common law there was such a power and that it had not been affected by legislation. The prerogative could be "affected" in two ways: a power could be abolished, or statute could give the Crown an alternative basis for acting, on which it must then rely so long as the statutory power remained extant.[3] Today, it is for the courts to decide whether or not and to what extent a prerogative power has been superseded by statute.[4] It should perhaps be noted, for completeness, that prerogative powers can atrophy—the power of impressment into the navy is the usual example—and that the courts can subject the exercise of some prerogative powers to judicial supervision.

5.  The nature of the prerogative can be summarised here as

  • Personal discretionary powers, including the rights to advise, encourage and warn Ministers in private; to appoint the Prime Minister and other Ministers; to assent to legislation; to prorogue or to dissolve Parliament; and (in grave constitutional crisis) to act contrary to or without Ministerial advice;
  • The legal prerogative, including the principle that the Crown (or the state) can do no wrong, and that the Crown is not bound by statute save by express words or necessary implication;
  • Certain executive powers, evolving historically from the constitutional convention that the Monarch acted on Ministerial advice, so that prerogative powers came to be used by Ministers on the Sovereign's behalf. Parliament was not directly involved in that transfer of power. Without these powers governments would have to take equivalent authority through primary legislation.

6.  The principal executive powers include the making and ratification of treaties; the conduct of diplomacy; the governance of British overseas territories; the deployment and use of the armed forces overseas, including involvement in armed conflict or the declaration of war; the use of the armed forces within the United Kingdom to maintain the peace in support of the police; the Prime Minister's ability to appoint and remove Ministers, recommend dissolutions, peerages, and honours (save for the four Orders within The Queen's own gift); and the issue and revocation of passports.


7.  In relation to the prerogative, the principal elements of the Bill of Rights 1688 were the abolition of some powers (such as the suspending and dispensing powers) and the modification of others (such as requiring parliamentary authorisation to raise money by taxation or to maintain a standing army). Modern examples of erosion of the prerogative include the War Damages Act 1965 which amended the power to take property in wartime by removing any obligation on the Crown to pay compensation. The immunities from legal proceedings enjoyed by the Crown under the prerogative were abolished and amended by the Crown Proceedings Act 1947. The European Assembly Elections Act 1978 imposed a requirement of parliamentary authorisation for certain European treaties before they could be ratified under the treaty-making prerogative.

8.  The courts have held that new prerogatives may no longer be created (though a definitive list of what the remaining powers are is lacking). It is sometimes the case that the courts will hold that a prerogative power has survived even though there is legislation in the same field (Northumbrian Police, paragraph 4 above and footnote 4). The courts have not challenged the right of Parliament to intervene to alter or remove the prerogative, and there is no constitutional obstacle to Parliament doing so with respect to the deployment power.



9.  "War" is a term that has both popular and legal connotations. Colloquially, "war" embraces conflicts between the armed forces of states and, occasionally, major internal conflicts such as the British or American Civil wars. "War" as a legal institution is a feature of both international and national law. In international law, the distinguishing characteristic of "war" is the legal equality of the belligerents and the special status of those states not taking part in the conflict ("neutral" states). The condition of "war" could be brought about by a declaration of war but one was not necessary (nor, where there was a declaration of war, were hostilities inevitable). Additionally, states could choose to regard a conflict between them as "war" and apply the legal rules accordingly, or neutrals could insist on respect for their rights. "War" as an institution of domestic law did require a declaration, made in the Monarch's name but by the Prime Minister, acting under the prerogative. This action triggered domestic consequences—nationals of the opponent state became "enemy aliens", liable to measures of restraint including detention. Property of enemy aliens was liable to seizure. Statute provided for emergency measures—for the call up of troops, the sequestration of property and so on.

10.  The United Kingdom has made no declaration of war since that against Siam (modern Thailand) in 1942, and it is unlikely that there will ever be another. Developments in international law since 1945, notably the United Nations (UN) Charter, including its prohibition on the threat or use of force in international relations, may well have made the declaration of war redundant as a formal international legal instrument (unlawful recourse to force does not sit happily with an idea of legal equality). The courts have recently decided that, as a matter of our constitutional law, the United Kingdom is not at war with Iraq because there has not been a declaration of war. In this report, when we use the word "war", we use it in the popular sense, conscious of its limitations as a definition suitable to our purposes in the modern world. Otherwise, we shall refer to "armed conflicts", both international and internal, to cover those situations not falling within the popular idea of "war" but where British forces are sent in anticipation that they will or may be involved in lethal exchanges of force or where British air or naval force is used against targets in another state or in international waters. While "international" and "internal armed conflicts" have become terms of art in international law, we do not use them here in their strict legal sense but by reference to an assessment of the risk of military action by British forces.


11.  This report is concerned with military activities outside the United Kingdom. It does not deal with use of the armed forces in aid of the civil power in the United Kingdom. When, today, states use their armed forces to promote their own or common interests internationally, such activities would not always fall within even the most elastic popular conception of "war"; but they may nonetheless involve risks to the lives of British troops and those against whom they are authorised to act. We describe some of these operations in paragraph 27. The categories of "armed conflicts" are so various and the risks so different that generalisation may be difficult, but the thread which holds them together is that the State contemplates that its armed forces will be sent into action abroad in the course of which they may have to kill and to risk being killed. Sometimes forces will be sent to "conflict" locations where a state of war exists or is anticipated. But there are circumstances when deployment is not expected to involve the use of force (for example peacekeeping) but where the possibility—and the risk of casualties—exists. A third category is when forces are deployed to locations where there is no real risk of armed conflict, for example to assist with humanitarian relief. Finally, forces may be deployed abroad for training, representational or other similar non-combatant purposes. In all cases, however, the decision to deploy is exercised under the prerogative. The power to commit those forces abroad will be referred to in this report as the "deployment power".


12.  It is commonly accepted that the prerogative's deployment power is actually vested in the Prime Minister, who has personal discretion in its exercise and is not statutorily bound to consult others, although it is inconceivable that he would not do so in practice. In this report we and witnesses have variously used such terms as "the executive" or "the government" in referring to the exercise of the power. Except where the context plainly indicates otherwise, these two phrases, and "the Prime Minister" should be regarded as mutually interchangeable.


13.  In addition to these definitions, we identify an important exclusion. Constitutionally, the armed forces of the United Kingdom are the forces of the Crown and the Monarch is the Commander in Chief. Thus, the prerogative over their disposition not only includes the ultimate power to send forces to war but operational questions regarding, for instance, their formation and armaments. The majority of witnesses who advocated change to the exercise of war-making powers by transferring them to Parliament sought to create limitations to the exercise of the deployment power itself, but not to the way in which operational matters are decided. Asked to comment on the proposition, witnesses in general, including all those with a military background, were of one mind in declaring that operational control had to remain with the professionals[5]. We acknowledge and endorse this position and do not, in this report, question the principle that the conduct of military operations—as opposed to the decision to mount them—should remain the exclusive responsibility of military commanders. At the same time we should add that, clearly, the greater the clarity on the part of Government of their objectives in determining the mission objective, the more this assists military commanders in executing that responsibility.


14.  The power to deploy the armed forces is not absolute. The Government are of course subject to certain constitutional constraints, including the general principle of their accountability to Parliament for the exercise of their powers. Government may also require the agreement of Parliament for financial provision for military deployment, although this was a more significant check on the Monarch's exercise of the prerogative in the past than it is for any Government which commands a majority in the House of Commons. Supply for deployments may be obtained from within the ordinary defence appropriation or from the contingency fund in an emergency. Otherwise, it is an item in the Budget, sometimes subject to special funding arrangements. The additional costs of spending in Iraq have been met from a special reserve set aside by the Treasury in 2003 and topped up from Budgets since. For instance, the Budget in 2006 contained provision for £800m for Iraq and Afghanistan and other international commitments and £200m for peacekeeping. In answer to a question about Afghanistan, the then Secretary of State for Defence said:

"When we have embarked on unexpected deployments—and over a period of years until 9/11, Afghanistan was unexpected—the Chancellor has been prepared, sometimes under very difficult circumstances, and in addition to the money spent on maintaining the defence posture, to support Her Majesty's armed forces in the tasks that this House asks them to carry out."[6]

15.  Judicial rulings from 1985 removed the complete insulation of the exercise of prerogative powers from review by the courts, although there is a lack of clarity over which of them might be subject to judicial control, and to what extent. Some powers however remain beyond judicial review because there are no legal standards by which to assess their exercise. Among these are the powers to make treaties and defend the realm.[7] In chapter 2 we look in more detail at the legal constraints on the deployment power, but note here that while the occasions have been few, the domestic courts have consistently held that the exercise of the umbrella power of deployment and its various subsidiaries are beyond their supervision.[8]

16.  In summary, the deployment power's status as a prerogative power means that there are few restrictions to its use, other than those that have arisen from precedent or convention. Parliament has no formal role in approving deployments, although governments have usually kept Parliament informed about the decision to use force and the progress of military campaigns[9]. The decision to invade Iraq in 2003 was the first time Parliament had voted on a substantive motion to deploy forces into conflict before fighting had begun since the Korean War in 1950. While the armed forces are technically subject to statutory control because legislative authority is needed for the Crown to maintain a standing army in time of peace, their use is for the Government alone to decide. Generally speaking, however, the deployment power is one to which no statutory or legal standards can be applied, and the courts have been reluctant to use arguments based on international law as a standard for assessing the legality of government decisions.[10] It is difficult to envisage how legal standards could be established, since precise lines cannot easily be drawn between the various tactical operational decisions that might be taken—for example to send troops into that town today, or to use air power rather than artillery. Even a decision to commit armed force at all may be qualitatively less significant in a legal sense than major in-theatre operational decisions, for example to escalate an existing conflict or to extend an area of operations. One only needs to recall the "Belgrano" incident during the Falklands campaign to see how controversy may develop.

17.  British forces are nowadays rarely deployed overseas by unilateral British governmental decision. There have been instances of deployments of wholly British forces following a solely British decision, for example the Falklands in 1982 and Sierra Leone in 2000, but more often deployment is part of coordinated action in partnership with allies (whether or not through an international organisation like NATO). In some cases, such deployments have lacked formal authorisation—in international law terms—like UN Security Council (UNSC) resolutions. In other cases, the UNSC may establish a UN force to which states might contribute their armed forces for peace-keeping or peace-building (such as the UN Protection Force in Bosnia-Herzegovina between 1992-95), or it may authorise one or several states to use force with a mandate and on conditions set out by itself (for example the authorisation to states to use force in support of Kuwait in 1991).[11] Such "multilateral" operations might involve many thousands of personnel, from all the armed services, down to a handful from a single service. In evidence, the Geneva Centre for the Democratic Control of Armed Forces drew attention to what it called the "double democratic deficit" of the use of force under such international auspices, arguing that there was inadequate accountability at the domestic level in some states, not compensated for at the international level of decision-making[12].

18.  Although some witnesses have suggested that the entire class of prerogative powers requires re-assessment, and this was also the view of the House of Commons Public Administration Select Committee in its report two years ago,[13] in this report we focus solely on the power to deploy armed forces overseas. This is arguably the most serious decision that can be taken by a government, and we hold the view, shared by several witnesses[14], that its consideration should be given priority, especially because of the public concern that has been expressed on the subject since the decision to join the coalition which invaded Iraq in 2003. Our focus on one prerogative power, rather than the entire class, also reflects the reality that the historical process of transforming the status of prerogative powers has, for the most part, been an incremental and evolutionary one. It has also attracted the most interest from parliamentarians—private members bills on or including proposed measures on the matter have been sponsored by Neil Gerrard MP, the Rt Hon Tony Benn, Lord Lester of Herne Hill and, in the current parliamentary session, the Rt Hon Clare Short MP (see paragraph 80).

19.  The United Kingdom's constitution is a combination of statute, common law and unwritten convention, with the result that it is flexible and constantly evolving. There are therefore dangers in seeking to compare our constitutional practice with that of other nations, most of which have written constitutions with complex procedures for their amendment, and there is perhaps only limited advantage in trying to draw lessons from them. Nevertheless, there is a greater degree of parliamentary involvement in deployment decisions in some other countries, and information about their practice can be instructive. We therefore attach at Appendix 4 a summary of the processes followed by other states in reaching decisions on the deployment of military force overseas.

1   Taming the Prerogative: Strengthening Ministerial Accountability to Parliament, Fourth Report, Session 2003-04, 16 March 2004, HC 422 Back

2   Government Response to the Public Administration Select Committee's Fourth Report, July 2004, HC 1262 Back

3   Attorney-General v De Keyser's Royal Hotel [1920] AC 508 Back

4   R v Secretary of State for the Home Department ex p Northumbrian Police Authority [1989] QB 26 Back

5   For example, Field Marshal Lord Bramall (Q117): "… under no circumstances must parliamentary approval be allowed to go into the tactical field or … the way you carry out the operation" Back

6   HC Hansard 26 January 2006 col 1546. Back

7   Council of Civil Service Unions v Minister for the Civil Service [1985] AC 374 Back

8   See, for example, Chandler v DPP [1964] AC 763; Campaign for Nuclear Disarmament v Prime Minister (CND) [2002] EWHC 2759 (QB). Back

9   A useful, but selective, summary of parliamentary debates on military deployments since 1939 can be found in the House of Commons Library research paper 05/56 of 8 August 2005  Back

10   For a recent example, see R v Jones et al [2006] UKHL 16, where the criminality under international law of the attack on Iraq was not pursued by the court. Back

11   UNSC resolution 678. Back

12   Volume II: Evidence, Page 213; H Born and H Hanggi, "The Use of Force under International Auspices: Strengthening Parliamentary Accountability", Geneva Centre for the Democratic Control of the Armed Forces, Policy Paper No.7, 2005) Back

13   Taming the Prerogative: Strengthening Ministerial Accountability to Parliament, Fourth report, 2003-04, HC Paper 422 Back

14   For example, Tony Benn QQ 2, 4; Clare Short Q 4; Peter Facey Q 180 Back

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