I am trying to research this for a friend.

I understand that the Government of the United Kingdom is a constitutional monarchy, in which the Queen is the head of state and the Prime Minister is the head of government. Currently, the Queen is the commander-in-chief.

  • Who has the authority to order the military?

  • Does the Prime Minister have to confer with the Queen before any action can be taken?

  • Or, vice-versa, can the Prime Minister order without the Queen's approval?

  • Or must both agree before any action can be taken?

  • Also, who has the ultimate authority over the nuclear weapons of the United Kingdom? In the United States, the ultimate authority is the President or the Acting President.

  • I will let a British expert write an authoritative answer, but according to Wikipedia and references therein, it's the PM: see en.wikipedia.org/wiki/… and en.wikipedia.org/wiki/…. In theory the Queen might have the power to countermand the PM, but as this has not happened in modern times, it's probably not clear who would actually win out. Jun 20, 2015 at 22:40

2 Answers 2


Of course, as you already are aware, the United Kingdom is a Constitutional Monarchy. Her Majesty Queen Elizabeth II, Queen of the United Kingdom and the other Commonwealth Realms is the Head of State, and the Prime Minister (currently David Cameron) serves as Head of Government.

Unlike other Commonwealth Realms, such as Australia (with the Australia Act 1986) and Canada (with the Canada Act 1982), the United Kingdom still has the 'royal prerogative'. The royal prerogative is the customary authority and privilege recognized in the United Kingdom as the sole prerogative of the Sovereign (i.e. QE II). This prerogative extends to defence, foreign affairs and national security.

However, since the 19th century, by convention, this prerogative is no longer exercised by the monarch acting on his or her own initiative. Now, the advice of the Prime Minister or the Cabinet - who are then accountable to Parliament for the decision - has been required in order for the prerogative to be exercised.

This being said, the Monarch still remains constitutionally empowered to exercise the royal prerogative against the advice of the Prime Minister or the Cabinet, but in practice would only do so in emergencies or where existing precedent does not adequately apply to the circumstances in question.

So, where does that leave us? Essentially, the Prime Minister can order the firing of the UK's nuclear weapons, and, without the approval of Parliament, send the country to war and make peace. However, it is unlikely he/she would do so without consulting with the Queen, who is currently kept 'in the loop' with government affairs by way of a weekly audience with the Prime Minister.

Leyland best sums up the case surrounding this issue in saying:

"[But it] should be emphasised that the prime minister is not under any obligation to take account of royal opinions."

Summary: The PM and Cabinet make the decisions. They keep the Queen in the loop. She can reject the decision made by the PM and Cabinet under her royal prerogative. In this case, it is uncertain what would occur.

  • 1
    So can they go on anyway if the queen refuses? That is the main question here...
    – Jose Luis
    Jul 22, 2015 at 10:14

It's debatable as the UK government has the power to move troops and decide on the military budget. But only the queen can declare war or peace and has the authority to give the armed forces their orders. Yet if she was to make a decision or give orders without government consent the government would probably stop her orders from being carried out

PS: all British, Canadian and Australian service personnel swear allegiance to her and her only and I know a lot of serving personnel who consider themselves to serve the queen and not the government.

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