Does parliament get a vote on military intervention?

13th Apr 2018


There is no constitutional requirement for a Parliamentary recall or vote before military intervention.


Correct. There’s no legal requirement that parliament is involved in these decisions, the power rests with the Prime Minister, through the Crown.


It has become convention that Parliament authorises military action when the UK is not in imminent danger of an attack.


Mostly—this has been argued by governments since 2011. But there’s still some question over which circumstances the convention applies under, and it’s not legally binding.

Claim 1 of 2

“In the abstract there’s no constitutional requirement either for a Parliamentary recall or for a parliamentary vote [for military action].”

Jo Johnson MP, 12 April 2018

“In a situation where there isn't that [imminent danger of an attack]... [it] has become the convention that Parliament is the place to authorise military action.”

Barry Gardiner MP, 12 April 2018

The Prime Minister has the power—through the Crown—to decide when to take military action. There’s no legal requirement that parliament is involved.

The House of Lords Constitution Committee says that:

"The decision to engage in armed conflict is one for the Government; Parliament has no legal role in authorising or approving the use of the armed forces overseas"

However, since 2011 governments have argued for the convention that military action be put to a parliamentary vote in non-emergency cases. There is no formal legislation asserting this, but the government has put three interventions to a parliamentary vote since 2013.

Most of the information in this article is drawn from this House of Commons Library briefing.

The Prime Minister alone has the power to deploy troops

The government has legal authority over how to deploy the armed forces. This power is vested in the government by the Queen.

In cases of a declaration of war, or committing armed forces to military action, then it is the Prime Minister alone who has the power to take that decision. Constitutional convention asserts that the Prime Minister takes that decision on behalf of the Queen, with consultation from the Cabinet, and advice from the National Security Council and the Chief of Defence Staff.

The Iraq War gave parliament a vote for the first time in recent history

But in the last fifteen years, parliament has started to play a greater role in deciding whether or not to deploy troops. Parliament does not have any legal authority to approve or reject the deployment of troops, but the government may choose to seek parliamentary approval if it wishes.

The 2003 Iraq War “was the first example in modern times of prior parliamentary approval having been sought, and granted”, according to the House of Commons Library.

It also notes that the Iraq vote “was regarded by advocates of a formal role for Parliament as setting a precedent for any future decisions on military action.”

But the government hasn’t always sought parliamentary approval for military action since then

In 2011 the government said: “since the events leading up to the deployment of troops in Iraq, a convention exists that Parliament will be given the opportunity to debate the decision to commit troops to armed conflict and, except in emergency situations, that debate would take place before they are committed.”

However, this convention was not enshrined in any legislation. Troops were deployed in Afghanistan in 2006 without a parliamentary debate or vote, for instance.

In 2011, at the same time as the government was arguing for this convention, forces were deployed in Libya without a debate or vote. The government argued that the urgency of the situation demanded immediate action, and later tabled a motion seeking retrospective approval for the action, which was approved by parliament. 

Just after the deployment of troops in Libya in 2011, Professor Nigel White at the University of Nottingham, said:

“I don’t think there is a constitutional convention or unwritten law that Parliament should be consulted about conflict decisions… there is simply a very uneven trend of Parliament asserting itself towards greater consultation, greater debate.”

Recent developments

Since 2011, the government has sought parliamentary approval for military action three times: in 2013 (in Syria), in 2014 (in Iraq), and in 2015 (in Syria).

In the first instance, parliament voted against military action, and the government chose not to take action as a result.

Professor Nigel White said that vote “has been important for democracy because it showed that although executives have the legal power to go to war or to use force, they are increasingly concerned with gaining approval from the wider polity”.

In the 2013 and 2014 cases the government emphasised the importance of consulting parliament on military action, where possible. The position has been that parliament need not be consulted in an emergency, with then-Prime Minister David Cameron saying in 2014:

“it is important that a Prime Minister and a Government reserve the right to act swiftly without consulting the Commons in advance in some specific circumstances—for instance, if we had to prevent an immediate humanitarian catastrophe or, indeed, secure a really important, unique British interest.”

There have been military deployments since 2011 where the government has not consulted parliament. But in these cases (Mali in 2013, and Ukraine in 2015) the government argued that the situation did not involve combat troops and (in the Mali case) and was an emergency.

In 2016 the government ruled out formal legislation

In 2016, the government continued to argue that since 2011 “a Convention had developed in Parliament that before troops were committed the House of Commons should have an opportunity to debate the matter and said that it proposed to observe that Convention except where there was an emergency and such action would not be appropriate.”

However, it also decided at this time that it would not be codifying this convention into law. It cited concerns over freedom of government action and the possibility that it would make deployment decisions a matter of the courts, rather than government authority.

“After careful consideration, the Government have 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.”

This statement was made before Theresa May’s first government, so it’s not clear if it still reflects current government position.

This fact check is part of a roundup of BBC Question Time. Read the roundup.