Introduction
In the United Kingdom’s constitutional framework, the principle of parliamentary sovereignty dictates that Parliament is the supreme law-making body. However, the sheer volume and complexity of modern governance mean that it is impractical for Parliament to legislate on every single detail. As a result, Parliament often delegates law-making powers to other bodies. The laws created through this delegated power are known as subsidiary legislation, also commonly referred to as delegated or secondary legislation. This essay will explain the meaning of subsidiary legislation and its various forms. It will then discuss why it has become such an important and indispensable feature of the UK’s legal system. Finally, it will describe the principal parliamentary and judicial mechanisms that have been developed to control the use of these delegated powers, ensuring they are not abused and that the executive remains accountable.
The Meaning of Subsidiary Legislation
Subsidiary legislation is law made by a person or body under authority given to them by an Act of Parliament (Loveland, 2021). The Act of Parliament that grants this power is known as the ‘parent Act’ or ‘enabling Act’. While primary legislation (Acts of Parliament) establishes the broad principles and framework of the law, subsidiary legislation fills in the necessary technical and administrative details. This creates a two-tiered system of law, with Acts of Parliament at the top and the more detailed subsidiary rules sitting beneath them.
There are several forms of subsidiary legislation. The most common and significant type is the Statutory Instrument (SI). SIs are typically made by government ministers and are used for a wide range of purposes, from setting the date for an Act to come into force (commencement orders) to establishing detailed regulations on topics like food safety or working hours. For example, the Equality Act 2010 is a parent Act that gives ministers powers to make further detailed regulations via Statutory Instruments.
Another form is Orders in Council, which are made by the King on the advice of the Privy Council. In practice, this means they are made by the government. They can be used to give legal effect to certain European Union laws that were retained after Brexit or to make laws in times of emergency under the Civil Contingencies Act 2004.
Finally, by-laws are a form of subsidiary legislation made by local authorities or other public bodies to deal with matters within their specific geographical area. For example, a local council might create by-laws to prohibit the drinking of alcohol in public parks or to regulate local markets. These rules have legal force but are confined to the local area. The sheer quantity of subsidiary legislation is notable; thousands of Statutory Instruments are made each year, far outnumbering the Acts of Parliament passed in the same period (Joint Committee on Statutory Instruments, 2023).
The Importance of Subsidiary Legislation
The use of subsidiary legislation is justified by several practical arguments that highlight its importance in a modern state. Perhaps the most significant justification is that it saves valuable parliamentary time. Parliament does not have the capacity or time to debate every technical detail of all proposed laws. By delegating the power to fill in these details, Parliament can concentrate on scrutinising the main principles and policies contained within the parent Act (Elliott and Thomas, 2020). Without this delegation, the legislative process would become overwhelmingly slow and inefficient.
Secondly, subsidiary legislation allows for the use of technical expertise. Many areas of law, such as environmental protection, financial services, or public health, are highly complex and require specialist knowledge. It is unrealistic to expect Members of Parliament to possess the necessary expertise across all these fields. Delegating power to government departments allows civil servants and technical experts, who have the relevant knowledge, to draft the detailed rules required.
Thirdly, subsidiary legislation provides flexibility and allows for rapid responses. The process of passing an Act of Parliament is long and complex, whereas subsidiary legislation can be created, amended, or revoked much more quickly. This flexibility is crucial for adapting the law to changing circumstances, new scientific evidence, or emergencies. A clear example was the government's response to the COVID-19 pandemic, where a series of Statutory Instruments were used to implement and adjust lockdown rules, travel restrictions, and public health measures at short notice (HM Government, 2020).
Finally, by-laws in particular allow for local matters to be addressed by those with local knowledge. A local authority is better placed than Parliament in Westminster to decide on rules for its parks, transport, or town centres, as it understands the specific needs and conditions of its community.
Mechanisms of Control
While subsidiary legislation is essential, it raises a constitutional concern: it involves law being made by the executive (government ministers) and other unelected bodies, rather than by the democratically elected Parliament. This challenges the doctrines of the separation ofpowers and parliamentary sovereignty. To mitigate this risk, two main forms of control have been established: parliamentary control and judicial control.
Parliamentary Control
Parliament retains ultimate control because it can amend or repeal the parent Act at any time, thereby removing or altering the delegated power. Beyond this, Parliament has specific procedures for scrutinising subsidiary legislation as it is being made.
The parent Act itself will specify the level of parliamentary scrutiny required for any Statutory Instrument made under its authority. The two main procedures are the negative and affirmative resolution procedures. The negative resolution procedure is more common. Under this procedure, the SI is laid before Parliament and will automatically become law after a set period (usually 40 days), unless a motion to annul it (a ‘prayer’) is passed by either House (Statutory Instruments Act 1946, s.5). In practice, it is very rare for an SI to be successfully annulled. The affirmative resolution procedure provides a stronger level of scrutiny. An SI subject to this procedure must be actively approved by both Houses of Parliament before it can become law. This forces the government to find parliamentary time for a debate and a vote, ensuring a higher degree of oversight, but it is used for a minority of SIs, typically those which are more significant or controversial (Hutton, 2021).
Furthermore, Parliament has specialist scrutiny committees. The most important is the Joint Committee on Statutory Instruments (JCSI), which is comprised of members from both the House of Commons and the House of Lords. The JCSI’s role is to conduct a technical review of SIs, checking whether they comply with the powers granted by the parent Act. It does not consider the policy merits of the legislation, but instead reports to Parliament if an SI appears to be ultra vires (beyond the powers of the parent Act), if it is poorly drafted, or if it imposes a tax, for example. The House of Lords also has a Secondary Legislation Scrutiny Committee, which has a broader remit to examine the policy merits of SIs and draw attention to those that are particularly important or controversial.
Judicial Control
The courts can also control subsidiary legislation through the process of judicial review. Any person or body with sufficient interest in a piece of subsidiary legislation can challenge its legality in the High Court. If the challenge is successful, the court can declare the legislation void and unenforceable. The primary ground for a legal challenge is that the legislation is ultra vires, meaning the body that made the law acted beyond the powers delegated to it by the parent Act.
Ultra vires can be broken down into two types. Procedural ultra vires occurs when the law-maker fails to follow a procedure set out in the parent Act. For example, if an Act requires a minister to consult a particular organisation before making regulations, a failure to do so could lead to the regulations being quashed. A classic example is Agricultural, Horticultural and Forestry Industry Training Board v Aylesbury Mushrooms Ltd [1972] 1 WLR 190, where regulations were held to be invalid in respect to the mushroom growers because the minister had failed to consult their representative body as required by the parent Act.
Substantive ultra vires occurs when the content of the subsidiary legislation goes beyond the scope of the power conferred by the parent Act. The law-maker has done something that the Act did not authorise. For instance, if an Act gave a minister power to regulate the safety of bicycles, a regulation that attempted to ban cars from city centres would likely be ultra vires.
A further ground for judicial review is unreasonableness. Following the case of Associated Provincial Picture Houses Ltd v Wednesbury Corporation [1948] 1 KB 223, the courts can strike down a decision or a piece of subsidiary legislation if it is so unreasonable that no reasonable authority could ever have come to it. However, the threshold for Wednesbury unreasonableness is very high, and courts are generally reluctant to intervene on this basis, respecting the political judgment of the minister or public body.
Conclusion
In conclusion, subsidiary legislation is a vital tool of modern government in the UK. It refers to law made by bodies exercising powers delegated to them by Parliament, most commonly in the form of Statutory Instruments. Its importance lies in its ability to save parliamentary time, allow for technical expertise, and provide a flexible and swift method for making detailed law. However, its use presents a constitutional challenge by allowing the executive to make law. To address this, a system of controls has been developed. Parliament exercises control through the parent Act, the affirmative and negative resolution procedures, and the work of its scrutiny committees. The judiciary exercises control through judicial review, primarily on the grounds of ultra vires. While the effectiveness of these controls is a subject of ongoing debate, they form an essential part of the constitutional balance, seeking to ensure that delegated power is used responsibly and within the limits set by Parliament.
References
Elliott, M. and Thomas, R. (2020) Public Law. 4th edn. Oxford: Oxford University Press.
HM Government. (2020) The Health Protection (Coronavirus, Restrictions) (England) Regulations 2020 (SI 2020/350). Available at: <https://www.legislation.gov.uk/uksi/2020/350/contents/made>
Hutton, G. (2021) The affirmative procedure. House of Commons Library Briefing Paper, Number 8752.
Joint Committee on Statutory Instruments. (2023) JCSI Annual Report 2022-23. HC 301 / HL 280. London: The Stationery Office.
Loveland, I. (2021) Constitutional Law, Administrative Law, and Human Rights: A Critical Introduction. 9th edn. Oxford: Oxford University Press.
Agricultural, Horticultural and Forestry Industry Training Board v Aylesbury Mushrooms Ltd [1972] 1 WLR 190.
Associated Provincial Picture Houses Ltd v Wednesbury Corporation [1948] 1 KB 223.
Statutory Instruments Act 1946.
