The Role of Parliament in the UK Constitution: Authorising the Use of Military Force Contents

4Formalising the convention: legislation and resolution

69.Concerns about the uncertainties surrounding the post-2003 convention have led to calls to formalise it. Both legislation and a resolution of the House of Commons have been proposed as methods of formalising the convention.

70.One of the main recommendations from the Public Administration Select Committee’s report Taming the Prerogative was that the executive power in the royal prerogative be put on a statutory footing and “war powers” was singled out as one the first areas where this should be pursued. However, no specific legislation setting out the arrangements was proposed by the Committee in the report. The first serious consideration of formalisation through both legislation and resolution took place as part of the Governance of Britain series of papers under the last Labour Government.

71.The Governance of Britain, War powers and treaties: Limiting Executive powers consultation paper set out four draft options: legislation, a detailed resolution, a simple resolution, and a hybrid option.105 Following the consultation, the Government said that it favoured the detailed resolution option, but as Jack Straw noted in his evidence to the Lords Committee in 2013, the resolution was not passed as it faced opposition from the Ministry of Defence and, after the 2008 financial crash, the attention needed from Prime Minister Gordon Brown to push it through had not been available.106

72.Lord Hague told us that when the Coalition Government came to power in 2010 it set out from its first day to formalise decision-making in relation to military action and so established the National Security Council.107 Then in 2011, when closing the debate on a motion to approve the Government’s military actions in Libya, Lord Hague, then Foreign Secretary, said the Government would “enshrine in law for the future the necessity of consulting Parliament on military action”.108

73.Lord Hague told us that this commitment to put the convention on a statutory basis, had been in line with his “long-held view… about the royal prerogative in general”.109 But he also made clear that this was a commitment made with the full agreement and encouragement of Prime Minister David Cameron. The Coalition Government did not bring forward legislation and, as the Government’s written evidence noted, in 2016 the Government “concluded that the prerogative remained the appropriate mechanism for deploying military force”.110 The Secretary of State for Defence set out the reasons for the decision in a written ministerial statement.111 While Lord Hague was not party to that decision, he told us that he too had “reluctantly” come to the view that it was a mistake to set down the convention in statute. He explained that it became clear that “it was very, very difficult to frame all the contingencies that might exist, and there was a danger of decisions about military action ending up in the courts”.112

74.In 2014, while setting down the convention in statute was still Government policy, the Political and Constitutional Reform Committee published its final report in its Parliament’s Role in Conflict Decisions series. The report welcomed the commitment to enshrine the convention in statute, but said the Government’s priority should be to agree a resolution.113 To aid this, a draft resolution was annexed to the report.114 While the Government did not produce a response to the report, the 2016 statement by the Defence Secretary also ruled out a resolution.

75.In its written evidence to this inquiry, the Government said it was “mindful of the difficulties and risks” of formalising the convention, either by legislation or resolution. It further stated that, “Codifying the particular circumstances where Parliament should be consulted, and where it should not, would likely undermine our ability to act.”115

76.When asked about the Government’s opposition to formalising the convention through legislation or a resolution, both the Chancellor of the Duchy of Lancaster and the Minister for the Armed Forces emphasised the difficulties of future-proofing. The Minister for the Armed Forces described this as the “principal objection” as he said legislation could not cover “every single potential situation that we may face” and he did “not want to lose the flexibility to be able to react to situations I may not be aware of now”.116 The Chancellor of the Duchy of Lancaster added to this concerns about the exceptions and the need to be able to act with the element of surprise or in an emergency. He raised the problem that setting out the convention in law would create a risk of involving the courts, and that formalising the convention could risk operational flexibility.117 Finally, he noted that sometimes the information that affects a decision is secret intelligence and cannot be shared more widely.118 When asked specifically about a resolution, the Chancellor of the Duchy of Lancaster said:

The problem with it is, while it would carry greater flexibility than primary legislation, it carries the same problems in almost inevitably not being able to be drafted in a way that provides for all possible contingencies, particularly given how the character of conflict might change.119

77.However, while stepping back from commitments to legislative formalisation, both Lord Hague and Jack Straw considered that some form of codification was still important to reduce the uncertainties between the Government and Parliament in such a vital area of national policy.120 According to Lord Hague, such codification would provide greater democratic legitimacy, more robust accountability and scrutiny, and would ultimately lead to better decisions.121 He said that he thought that the convention could be improved; it could be codified in a way that avoided serious misunderstandings between Government and Parliament, as had happened in relation to Syria in 2013.122

78.While there was scepticism about the appropriateness of setting the post-2003 convention out in legislation, there were several advocates of a resolution being the best route forward. Professor Phillipson suggested that it would allow the House of Commons to consider what role it should have in a general constitutional sense, divorced from the controversies of a particular case, where the merits of the particular military action would be likely to interfere with thinking about the fundamental principles. It would also, he suggested, prevent the convention developing in a haphazard way, driven by the Executive and “short-term political exigencies”.123

79.Sebastian Payne said he thought there would be an advantage to having a resolution, as it would emphasise that this is a matter between Government and Parliament, and an Act of Parliament could change that position by including the courts.124 He thought that Parliament should consider how it could “add to the decision-making process in different scenarios and under what circumstances should it be left to the Government”.125 A resolution would formally set out what the convention was, and how it would be expected to function. The intention of passing a resolution rather than legislation would be that the convention would be given clearer political authority without placing legally-binding restrictions on the Government.

80.A resolution would not prevent a future government with a large majority from declining to follow the post-2003 convention as set out in that resolution.126 However, as Jack Straw stated in 2013, a resolution would set out not only to the House of Commons but also to the public, who he described as the “the owners of our constitutional arrangements”, where the power over military action should ultimately lie.127

81.The decision to deploy military force is an executive function, exercised in modern times by the Prime Minister in conjunction with the Cabinet. While we believe that the involvement of Parliament at the earliest possible stage of decision-making is vital, we consider that any statutory formalisation of this expectation would create new risks. Members of Parliament are not in possession of the depth and quality of information and confidential advice necessary to take on the role of primary decision-makers. We are persuaded by the evidence that any attempt to legislate for all possible contingencies and exceptions would lead to unintended and unfortunate consequences, including the unwelcome possibility of judicial review of government decisions as well as legal action against members of the Armed Forces and consequent uncertainty in relation to the deployment of military force, which could be detrimental to the national interest. We regard it as significant that two former foreign secretaries who had previously been committed to the principle of statutory formalisation have since changed their minds. The Government should, nevertheless, be held accountable for its actions and policies, and Parliament, and the House of Commons in particular, should continue to develop its scrutiny role.

82.We were not convinced by the Government’s arguments against setting out the post-2003 convention in a resolution of the House of Commons. We note the Government’s concerns in relation to the difficulty of anticipating all contingencies, and the need to adapt to the changing nature of conflict. These are strong arguments which preclude the legally enforceable constraints of statutory codification, but not the political constraints of a resolution of the House of Commons requiring a debate and a vote of the House of Commons. A resolution would provide both clarity and flexibility for the Government to act in ways not previously anticipated, but still within the spirit of the post-2003 convention and the exceptions.

83.We therefore recommend a resolution that would acknowledge the core convention and work in conjunction with agreed changes to practices in the communication between the Government and the House of Commons. We set out a draft resolution in paragraph 133. We also invite the Procedure Committee to consider whether the procedures of the House of Commons should be changed to allow the Government, in exceptional circumstances, to table without the customary minimum period of notice a motion seeking the authorisation of the House of Commons for military action, to be scheduled alongside previously announced business in similar fashion to the scheduling of emergency debates agreed to by the House under Standing Order No. 24.


105 The legislative option provided detailed processes and mechanisms for how approval should be sought and what the exceptions would be, and it also set out definitions for armed conflict and armed forces. The detailed resolution was very similar to the legislation, but relied on political and not legal authority to enforce it. The general resolution sets out the principle that the Government should seek approval from Parliament and that there are exceptions, but leaves out details of how the process should work. The hybrid option set out the obligation to seek approval from the House of Commons and definitions, but left the processes up to Parliament.

106 Oral evidence taken before the House of Lords Select Committee on the Constitution on 12 June 2013, HL 46, Q34 [Jack Straw]

108 HC Deb, 21 March 2011, col 799 [Commons Chamber]

110 Cabinet Office (UMF0022)

111 HCWS678 We cannot predict the situations that the UK and its Armed Forces may face in future. If we were to attempt to clarify more precisely circumstances in which we would consult Parliament before taking military action, we would constrain the operational flexibility of the Armed Forces and prejudice the capability, effectiveness or security of those forces, or be accused of acting in bad faith if unexpected developments were to require us to act differently…
… After careful consideration, the Government has decided
that it will not be codifying the Convention in law or by resolution of the House in order to retain the ability of this and future Governments and the Armed Forces to protect the security and interests of the UK in circumstances that we cannot predict, and to avoid such decisions becoming subject to legal action.

113 Political and Constitutional Reform Committee, Twelfth Report of the Session 2013–14, Parliament’s role in conflict decisions: A way forward, HC 892, 49

114 Political and Constitutional Reform Committee, Twelfth Report of the Session 2013–14, Parliament’s role in conflict decisions: A way forward, HC 892, Annex

115 Cabinet Office (UMF0022)




Published: 6 August 2019