1. This note seeks to describe as fully as possible the extent of the prerogative. However, as will become clear, the exact limits of the prerogative cannot be categorically defined. The note goes on to describe the way in which the exercise of prerogative power is controlled by Parliament and the Courts.
2. There is no single accepted definition of the prerogative. It is sometimes defined to mean all the common law, ie non-statutory powers, of the Crown. An alternative definition is that the prerogative consists of those common law powers and immunities which are peculiar to the Crown and go beyond the powers of a private individual eg the power to declare war as opposed to the normal common law power to enter a contract.
3. Whichever definition is used there is no exhaustive list of prerogative powers. Some have fallen out of use altogether, probably forever - such as the power to press men into the Navy. It may be of more practical assistance to identify those powers which have been consistently recognised by the courts in the past, mindful of the encroachment into the prerogative as a result of the control exercised by Parliament and the courts.
4. Although this is the area in which legislation has increasingly been introduced thereby limiting the extent of the prerogative, some significant aspects of the prerogative survive in the area of domestic affairs. These include:
the appointment and dismissal of Ministers;
the summoning, prorogation and dissolution of Parliament;
royal assent to Bills;
the appointment and regulation of the civil service;
the commissioning of officers in the armed forces;
directing the disposition of the armed forces in the UK;
the appointment of Queen's Counsel;
the prerogative of mercy. (This no longer saves condemned men from the scaffold but it is still used eg to remedy errors in sentence calculation) ;
the issue and withdrawal of UK passports;
the granting of honours;
the creation of corporations by Charter;
the King (and Queen) can do no wrong (for example the Queen cannot be prosecuted in her own courts)
5. The conduct of foreign affairs remains very reliant on the exercise of prerogative powers. Parliament and the courts have perhaps tended to accept that this is an area where the Crown needs flexibility in order to act effectively and handle novel situations.
6. The main prerogative powers in this area include:
the making of treaties;
the declaration of war;
the deployment of the armed forces on operations overseas;
the recognition of foreign states;
the accreditation and reception of diplomats.
Can the prerogative powers be extended?
7. The Crown cannot invent new prerogative powers. This is consistent with the residual nature of the prerogative. However, because the prerogative is not codified or frozen at a particular point of time, it can still to some extent adapt to changed circumstances. The Lord Privy Seal, in written answer in the House of Lords on 1st February 1996 to the question "what are the categories of powers exercised by ministers exclusively under the royal prerogative" said "the government shares the view of Wade and Bradley, in their work Constitutional and Administrative Law (11th Ed. 1993), that it is not possible to give a comprehensive catalogue of prerogative powers". This government also shares that view.
8. So there is scope for the courts to identify prerogative powers which had little previous recognition. In R v Secretary of State for the Home Department, ex parte Northumbria Police Authority  1 QB 26 (CA), the Court of Appeal examined the interaction between known prerogative powers and prerogative powers that might exist. The facts concerned the Home Secretary's power to issue baton rounds to a chief constable without the consent of the police authority.
The Court held that the 1964 Police Act gave the Home Secretary the power to do this but went on to hold that in any event the Crown had a prerogative power to keep the peace within the realm, which was not displaced by the 1964 Act, and the Home Secretary could therefore have acted even if the Act had not provided him with one. Nourse LJ commented that "the scarcity of references in the books to the prerogative of keeping the peace within the realm does not disprove that it exists. Rather it may point to an unspoken assumption that it does".
9. It is likely that the courts would be willing to recognise a wide range of necessary responses by the Executive to an emergency as authorised under the prerogative in the absence of a clear statutory basis. Indeed in Constitutional and Administrative Law (7th Ed. 1994)
De Smith and Brazier comment that it is clear that the Crown still has certain prerogative powers in time of grave national emergency to enter upon, take and destroy private property, though the conditions under which these powers are exercisable are far from clear, partly because the powers were never precisely defined, partly because the scope in time of war was not considered in general terms by the courts for nearly three hundred years, and partly because of the encroachment of various statutory provisions made over the years.
B CONTROL OF THE PREROGATIVE
Limitation of the Prerogative by Parliament
10. It is long established law that Parliament can override and displace the prerogative by statute. Where the Crown is empowered by statute to do something that it could previously do under the prerogative, it can no longer act under the prerogative but must act within the statutory scheme. The statute can, however, expressly preserve the prerogative. For example the Crown Proceedings Act 1947 contains an express saving at section 11 that the provisions of the Act shall not extinguish or abridge pre-existing prerogative powers (as well as powers conferred on the Crown by statute).
11. It is not altogether clear what happens where a prerogative power has been superseded by statute and the statutory provision is later repealed but it is likely to be the case that the prerogative will not revive unless the repealing enactment makes specific provision to that effect. And in practical terms, it seems virtually unthinkable that the Government would seek to rely on the prerogative to replace an Act of Parliament, except perhaps in a grave national emergency.
12. As the prerogative is a residual power it cannot be used to amend the general law. This is of particular interest in relation to international treaties. Although the Executive can commit the United Kingdom to obligations under international law, if a change to domestic law is required, it will only take effect if Parliament passes the necessary legislation.
13. Parliament also controls the exercise of the prerogative through its control of supply. The Executive has no practical ability to act unless it can fund its activities. What has become known as the Ram doctrine was set out in a memorandum by the then First Parliamentary Counsel, Sir Glanville Ram in 1945.
This explains that as a matter of law a Minister of the Crown may exercise any powers that the Crown has power to exercise, except to the extent to which the Minister is precluded by statute either expressly or by necessary implication. The ability of the Minister to spend money to exercise those powers will however depend on whether Parliament votes him the funds to do so.
14. Ministers exercising prerogative powers remain accountable to Parliament as they are for the exercise of power from any other source. The recent proceedings of the foreign affairs select committee demonstrate the scrutiny to which the exercise of the prerogative power can be put. Such accountability in itself is a form of control exercised by Parliament over the Executive.
15. If challenged, the prerogative must be recognised by the courts. They therefore define its limits and have jurisdiction to inquire into the existence and extent of any alleged prerogative. Whether powers derive from the prerogative or from statute, the courts recognise the limits of justiciability.
In Judicial Review of Administrative Action (5th Ed. 1995) Lord Woolf and Jeffrey Jowell describe those limits as follows: "Yet there are some decisions that the courts are ill-equipped to review; those which are not justiciable, either because they admit of no objective justification or because the issues they determine are polycentric in effect. Such decisions include those that necessitate the evaluation of social and economic policy, or the allocation of scarce resources among competing claims. Courts are institutionally unsuited to resolving these kinds of problem, which are best left to be decided in the political arena."
16. Until relatively recently the courts would not inquire into the way in which a prerogative power had been exercised. But, as judicial review has developed, this attitude has changed and the courts have become more willing to review the exercise of any discretionary power whatever its source. The courts are still reluctant to interfere with the exercise of the prerogative where this relates to "high policy".
In R v Secretary of State for Foreign Affairs ex p Everett  1 QB 811 Taylor LJ differentiated between acts involving matters of "high policy" at "the top of the scale of executive functions under the prerogative", and matters of administrative decision, affecting the rights of individuals and their freedom to travel, where we can expect more judicial scrutiny. The former category would include making war and mobilising troops; the latter the refusal to grant or renew a passport.
17. It remains impossible to define the exact limits of the prerogative. It is hoped that this note assists understanding by describing the main prerogative powers and the way in which their exercise is subject to checks and balances by Parliament and the courts.