What are the relationships and balance of power between the branches of government?
The relationships between the legislature, executive and judiciary, the role and powers of the Supreme Court, the doctrines of judicial review and parliamentary sovereignty, and the influence of the European Union on UK government.
A focused answer to AQA A-Level Politics on the relationships between the legislature, executive and judiciary, the role and powers of the UK Supreme Court, judicial review and judicial independence, and the historic and current influence of the European Union.
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What this dot point is asking
AQA wants you to explain how the legislature, executive and judiciary relate to one another in the UK, describe the role and powers of the Supreme Court since 2009, explain judicial review and judicial independence, weigh the doctrine of parliamentary sovereignty against the growing power of the judiciary, and assess how membership of the European Union affected UK government.
Separation of powers in the UK
Unlike the United States, the UK does not have a strict separation of powers.
The Constitutional Reform Act 2005 created an independent Supreme Court (operational from 2009), removed the judicial role of the House of Lords and reformed the office of Lord Chancellor, strengthening the separation between courts and Parliament.
The Supreme Court
The UK Supreme Court is the highest court of appeal for civil cases across the UK and for criminal cases in England, Wales and Northern Ireland. It interprets the law, hears cases of major constitutional importance, and determines the meaning of statute.
The Court cannot overturn an Act of Parliament, but it made high-profile rulings such as Miller (No. 1, 2017) requiring an Act of Parliament to trigger Article 50, and Miller (No. 2, 2019) declaring the 2019 prorogation of Parliament unlawful.
Judicial review
Judicial review checks the executive but respects sovereignty: a declaration of incompatibility does not strike down the law, it only invites Parliament to amend it.
Parliamentary sovereignty versus the judiciary
There is a continuing debate about whether the judiciary has become too powerful. Critics argue that activist rulings draw judges into politics; defenders argue the courts only enforce the law and protect rights, and that Parliament remains sovereign because it can legislate to reverse any ruling.
The influence of the European Union
While the UK was a member (1973 to 2020), EU law had supremacy over conflicting UK law, as established in the Factortame case (1990), which suspended part of an Act of Parliament. This was the most significant limit on parliamentary sovereignty in modern times.
Exam-style practice questions
Practice questions written in the style of AQA exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
AQA 20199 marksExplain and analyse three ways in which the judiciary checks the executive. (Paper 1, Section A, short-answer)Show worked answer →
Three distinct mechanisms, each defined, illustrated and analysed.
One: judicial review of ultra vires action. Courts can quash ministerial decisions taken beyond legal powers or unreasonably. Analyse that this enforces the rule of law but only operates within the bounds set by statute.
Two: declarations of incompatibility under the Human Rights Act 1998. Courts can declare a statute incompatible with Convention rights. Analyse that this respects parliamentary sovereignty (it does not strike down the law) yet exerts strong political pressure to amend it.
Three: rulings on the limits of prerogative power, such as Miller (No. 2, 2019) on prorogation. Analyse that the courts policed the boundary between executive and Parliament without overriding statute.
Markers reward three clearly different checks, accurate case examples, and analysis of how each respects parliamentary sovereignty.
AQA 202220 marksEvaluate the view that the UK Supreme Court has become too powerful. (Adapted from Paper 1, Section C essay; 25-mark essay rescoped to 20.)Show worked answer →
A balanced essay with a sustained judgement and developed arguments on both sides.
For too powerful: high-profile rulings against the government (Miller No. 1 and No. 2), the growth of judicial review and human rights cases, and the charge of judges entering political territory.
Against too powerful: the Court cannot strike down an Act of Parliament; parliamentary sovereignty means the government can legislate to reverse any ruling; judges enforce the law rather than make policy; and judicial independence and neutrality constrain them.
Markers reward a clear line of argument, accurate cases, weighing of the two sides, and a judgement that the Court checks but does not override Parliament. AO3 (evaluation) carries the most weight.
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Sources & how we know this
- AQA A-level Politics (7152) specification — AQA (2017)