Separation of Powers: A perspective from the British Constitution


It is Lord Diplock, one of the common-law world’s most significant judges, who in the British case of Duport Steels Ltd v Sirs [1980] stated, “the British constitution, though largely unwritten, is firmly based on the separation of powers. Parliament makes the laws, the judiciary interprets them.” This principle is a bedrock of Zambia’s constitutional order. This article seeks to highlight the attitudes behind this principle drawing upon the rich tradition of the British system.

One of the characteristics of the British constitution is that it is largely unwritten in the sense that it is not a single codified document. As such, the British constitution can be found in various statutes, case law, and conventions. The British constitution has also been affected by international treaty obligations such as the European Convention of Human Rights (ECHR) and the European Union treaties. At the heart of British constitutionalism is the doctrine of separation of powers.

In its simplest form, separation of powers is a doctrine that states that government comprises three branches each with distinct roles to play. Theoretically then, the legislative branch makes laws, the executive enforces them and then the judiciary interprets the laws. Philosopher Montesquieu, using the philosophy of John Locke, developed this doctrine. As the doctrine underlying the constitutional make-up of the United State of America and indeed the United Kingdom, three fundamental ideas undergird the doctrine of separation of powers.  First, the same persons should not form part of more than one of the three organs of government. Second, there should be no interference or control by one organ over the affairs of the other. And third, one organ of government should not exercise the functions of the other.

While the British constitution has largely held to the idea that “the same persons should not form part of more than one of the three organs of the government”, there have been some instances in which the same persons have formed a part of more than one organ of state. The requirement that the Cabinet should be drawn from among the members of the British legislature runs contrary and seems to contradict the doctrine that the same persons should not form part of more than one of the three organs. The same applies in Zambia where currently all members of the cabinet are also members of parliament. Indeed, the fact that the executive is made up of exclusively members of the legislature does mean that they cannot truly be independent of Cabinet or government direction once they are in the legislature. This, therefore, means that the work of these members of the legislature who are also members of the executive could potentially be interfered with by the machinations of the party and the executive.

In Britain, the Queen as Head of State is a part of parliament as well. While the Monarch’s powers in terms of government are highly ceremonious it is clear that the Monarch’s membership of Parliament and the executive government is a theoretical abrogation of this principle of separation of powers.

Separation of powers seems to be contradicted in Britain, by the fact that for many years in the British constitutional history, members of the Highest Court of the land where also members of the House of Lords, which is a part of the British Parliament. However, in spite of the House of Lords doubling as both legislature and highest court at the same time, judges within the House of Lords were mostly kept from doing partisan politics, albeit by tradition. In 2010, following the Constitution Reform Act 2005, a new Supreme Court replaced the Judicial Committee of the House of Lords to become the highest court of the land. This action has further bolstered the fact that judges of the highest court of the land should not be members of the legislature. In Zambia, we never had those issues in the first place.

For many years the Lord Chancellor, in fact was not only a member of the executive, but he was also a member of the judiciary and of the legislature as well. This historical inconsistency however, has been altered under the Constitutional Reform Act 2005. The Lord Chancellor is not the head of the judiciary under the new law.

The next undergirding idea to the separation of powers, states that one organ of the state should not interfere or control the affairs of the other in the British constitution. In terms of control or interference, the judiciary has remained to a large extent independent of control by either the legislature or the executive. The executive is never expected to control the judiciary. In instances where the judiciary has been called upon to rule on the actions of the legislature, they have given deference to the legislature. They have in most instances upheld the supremacy of parliament.

When Lord Diplock stated that the legislature makes laws while the judiciary interprets the laws, he clearly meant that in the British Constitution these two organs should not exercise the functions of the other.

While this has held true at theoretical level, it is clear as demonstrated above that in fact, these two organs have exercised functions of the other on several occasions.

In England and Wales, sources of the Constitution are multiple. Parliament is just one of those sources. Since our common law system puts lots of emphasis on precedence and case law, it is clear that in the exercise of performing their judicial roles, judges in fact do make law.

Judges, thereby, not only interfere with the functions of the legislature but also perform the functions of the other organ of government. While many judges do want to give the impression that their role is only to interpret the law, it is clear that the consequences of that interpretation do in fact have legislative effect. This remains the case in Zambia.

The challenge for Zambia is that it remains true to the constitutional ideals of separation of powers.

Our country has borrowed a great deal from the British constitutional order. As we formulate a new constitution in 2015, it is important that we uphold the values found in this principle.