The Royal Prerogative are functions that ministers carry out that have their power derived from the monarch. This is part of the British Constitution.

Royal Prerogative powers in Britain are:

There may be many more for Britain since most powers that Parliament (and therefore the Prime Minister) have been removed from the monarch and are now in their hands.

These powers are theoretically still what the monarch can do and she/he has merely delegated them to others. In practice, however, the monarch tends to just agree to what Parliament decrees.

The Royal Prerogative is an important thing for a subject of Britain to understand. The current political system of Britain means that the Prime Minister can use his/her prerogative powers without the consent of the Cabinet or Parliament. Therefore, if Tony Blair wishes to follow America and declare war on Iraq then he can. No shouting from the Commons or the Lords can stop him. This is contrary to the American system where such powers held by the executive (the President) often have to be rattified by Congress. For example, appointments to offices in the government made by the President have to be ratified as well as calls to war. Even treaties made by the President can be over ridden by Congress.

I weep for Democracy in Britain.