Is the doctrine of the separation of powers a useful doctrine in the context of the British Constitution? How has this doctrine fared in recent years? The doctrine of the separation of powers ensures that the liberty of the individual is secure only if the three primary functions of the state (legislative, executive, and judicial) are exercised by distinct and independent organs. The doctrine was propounded by Montesquieu (De l'Esprit des Lois, 1748), who regarded it as a feature of the British constitution. It is a concept which has a superficial simplicity, but at the same times a rather deep complexity. It contains both a descriptive and prescriptive element; the concept has a long history in political thought, right back to the time of Aristotle. The conscious adaptation of the "separation of powers" principles by the framers of the American constitution in the late 18 th century ensured its importance in subsequent constitution making. It is based on the idea that there are three classes of governmental function, each carried out by a distinctive organ of government.

In descriptive terms these are; 1. ) Executive function, carried out by the executive (government), 2. ) Legislative function, carried out by the legislature (parliament, assembly), and 3. ) Judicial function, carried out by the judiciary (courts). The prescriptive or normative element has two parts in it; 1. ) the three functions should be operated by three organs of government, and 2.

) to allow some (or, on some views, any) mixing of the three functions and, in particular, the three organs is a threat to liberty. There are wide ranges of ways in which the doctrine can be applied, or indeed not applied as the case may be in the context of the constitution. At one extreme there could be a complete mixing of all of the functions in one organ, or indeed one person such as a dictator or absolute monarch. At the other extreme is the idea of absolute separation, which has absolutely no overlapping of function or persons. A constitution which seeks to apply the latter idea may well, as in the example of the United States incorporate various checks and balances to ensure that no single arm of government can reign supreme over the other, while also providing for some level of interdependence to ensure the effective operation of the government by the various organs. Between these two extremes lies the British constitution where there is quite a clear and evident degree of the mixing and the overlapping of the functions and organs of government.

In the context of the British constitution I find if practically impossible to identify the boundaries of the doctrine of the separation of power. In 1690, the Englishman John Locke wrote in his Second Treatise of Civil Government: "It may be too great a temptation to human frailty, apt to grasp at power, for the same persons who have the powers of making laws, to have also in their hands the power to execute them, whereby they may exempt themselves from obedience to the laws they make, and suit the law, both in its making and execution, to their own private advantage" In the context of the British constitution the idea of 'mixed government' is that it is the degree of connection, rather than the degree of separation, that itself provides the checks and balances which are necessary to prevent government tyranny and preserve individual liberty. It is my belief that the key governing principle for the separation of powers is the imposition of cheques and balances. If each branch of government can check the other branch to ensure that no one branch is in breach of its power then there appears to be an authoritative level of checking. The executive cannot interfere with the rights of the citizens without any statutory power, so the courts can therefore check the executive by using their power to interpret legislation. It is difficult to talk about the separation of powers and not stumble across the issue of judicial review; the development of this kind of judicial review is based solely on the notion of judicial supervision of the legality of administration, rather than of primary legislation.

Although it may seem that this kind of judicial review doesn't involve a challenge to parliament's legislative supremacy, it is a way of challenging how these laws are implemented and administered. In the past 30 years this type of judicial review has undergone rapid development and there is a clear willingness among the courts to tackle controversial and important political issues such as deportation and immigration cases. The Thatcher government of 1987 responded to the surge in judicial review cases by producing a guide for Whitehall called The Judge over Your Shoulder. In an responding article in the Guardian, Richard Norton-Taylor writes; "The delicate balance between Parliament, the executive, and the courts is under severe strain.

It is a dangerous development, encouraged by Mrs Thatcher's style of government and a determination to tighten control over civil servants and the disclosure of information to MPs. It is being fed on the weakness, and sometimes simply the disinterest, of the Commons. Judges, whether they like it or not, are increasingly being forced into the political arena" The jurisdiction of such highly controversial political and social issues can often be seen to put the judges in direct conflict with ministers and parliament, putting to the test, the boundary line between parliament and the courts. In some cases, cases which tend to be highly significant conservative judges will step back and state that this particular matter should be settled not by the courts of law, but by political means.

It is common for judges to employ a separation of powers language to explain or justify their decision, especially interpretation, such in steel strike case where Lord Diplock commentated; "At a time when more and more cases involving the application of legislation which give effect to policies that are the subject of bitter public and parliamentary controversy, it cannot be too strongly emphasised that the British constitution, though largely unwritten, is firmly based on the separation of powers. Parliament makes laws, the judiciary interprets them. When parliament legislates to remedy what the majority of its members perceive to be a deficit or lacuna in the existing law, (whether it be written law enacted by existing statutes or by the unwritten common law as it has been expounded by the judges in decided cases). The role of the judiciary is confined to ascertaining from the words that parliament has approved as expressing its intention, what that intention was and to giving effect to it, where the meaning of the statutory words are plain and unambiguous it is not for the judges to invent fancied ambiguities as an excuse for failing to give effect to its plain meaning because they themselves consider that the consequences of doing so would be inexpedient, or even unjust or immoral. In controversial matters such as those involved in industrial relations there is room for differences of opinion as to what is expedient, what is just and what is morally justifiable. Under our constitution it is parliaments opinion on these matters that is paramount" It is notable that the use of the word "Parliament" by Lord Diplock in this context is strictly accurate in a constitutional theory.

It can go as far as to mask the political reality that legislation is usually that of the government of the day, rather than some autonomous body known as parliament. The dispute of the courts is therefore, at least in practical terms is often with the political executive rather than with parliament as such.