The doctrine of parliamentary sovereignty, defined by Dicey as parliament having ‘the right to make any law whatever; and, further, that no person or body is recognised by the law of England as having a right to override or set aside the legislation of Parliament’, is still a cornerstone of the constitution.[1] However, the absolute terms in which Dicey described this is incorrect today.

Where parliament can in theory pass or repeal any Act, it is no longer the case that Acts of Parliament are the only statutes with the highest legal authority, and it is no longer the case that all statutes are equal and incapable of being struck down – if over-ruled in European law.

The limits of the traditional definition

The Statute of Westminster 1931 gave certain British dominions legislative independence. Section 4 of the Statute provides that no Westminster Act of Parliament may extend to a dominion without the consent of the parliament of that dominion, limiting the power of future Westminster parliaments.[2] Where this could be expressly repealed by the Westminster parliament, it could be seen as cementing a constitutional convention – that Westminster does not alter domestic law in Commonwealth states without consent of that state’s parliament. Perhaps this is a little stronger than a convention; the powers given by the Statute of Westminster allowed former dominions to extinguish the practical ways in which a Westminster Act could be enforced (by the end of the next parliament, De Valera’s constitution had taken affect in Ireland which would have made enforcing anything that Westminster chose to legislate on impossible). Regardless, there is nothing stopping Westminster from passing an Act regarding a territory it has no control over that has no chance of being enforced.

Similar conventions on what Westminster cannot legislate for have been created since, for example that Westminster will not legislate on devolved matters without consultation.

These conventions are not legally binding, but are seen by those involved in the legislative process as binding – to different degrees. For example a member of the House of Lords could legally Prime Minister, but the convention that the Prime Minister must be an MP was seen as binding when the Earl of Home became Prime Minister in 1963. Days after becoming Prime Minister, Earl Home renounced his peerage under the Peerage Act 1963 to fight a by-election for a House of Commons seat. Due to the importance placed on the convention that a Prime Minister must be an MP, it meant that he was briefly Prime Minister while not a member of either house while parliament was sitting; the first and only time in modern British history.[3]

Conventions act to flesh out much of our unwritten constitution in this way; certain conventions fill in gaps of practicality or legitimacy that legislation can or will not fill, and in effect do bind parliament and those in it through political means rather than legal means.

The European dimension

The European Communities Act (ECA) 1972 allowed the UK to formally join the European Community, which would become the EU, in 1973. The Act enabled EU/EC regulations and some directives (that adhere to the conditions of Van Duyn, and Marshall) to be automatically implemented as part of UK law, as delegated legislation.


Historically, legislation was interpreted by judges under the assumption that it did not intend to repeal the ECA when a conflict between British and European law did occur. For example Pickstone v. Freemans, where the House of Lords held that a literal interpretation of UK employment statutes was inappropriate, and a purposive approach should be used to interpret legislation when there was a conflict.[4]

R (Factortame Ltd) v Secretary of State for Transport would not allow for this type for interpretation, however.[5] The case revolved around a clearly expressed section of the Merchant Shipping Act 1988, which placed substantial and clear limitations on the ability of non-British citizens to own British fishing boats. These limitations were in contravention of an EC directive.

Lord Bridge in summing up the Factortame case said that the ECA had made it the UK court’s duty to over-rule non-compliant domestic statutes in favour of European law.[6] The reasoning behind it – that the ECA made all future European law superior law in the UK – suggested that parliamentary sovereignty now only existed insofar as parliament could expressly repeal the entire ECA, and that parliament was not able to legislate on any issue that Europe had already legislated on without repealing the ECA.

The explanation was expanded upon and altered in Thoburn v Sunderland City Council, in which market traders argued for their right to continue using imperial measurements, allowed in the Weights and Measures Act 1985. The 1985 Act was superseded by EU Directive 80/181/EEC in 1994, becoming law through the provisions of the ECA. They argued that the 1985 Act was implied repeal of part of the ECA, and the 1994 directive was therefore invalid.[7]

Lord Justice Laws, in obiter dicta statements, said that there was a hierarchy of Acts of parliament; at the top are the ‘constitutional statutes’ which require express repeal, including the ECA.[8] In BH v The Lord Advocate (Scotland), Lord Hope echoed the logic of this case in orbiter dicta statements, saying that the Scotland Act 1998 had become a ‘constitutional statute’ that could only be expressly repealed.[9]

The European dimension has created a new authority for superior law in England. Laws with the same weight as an Act of Parliament can be created by the European Commission, which can over-rule previous Acts through implied repeal but are protected by the ECA’s status as a ‘constitutional statute’ from implied repeal themselves – although not from express repeal.

Parliamentary sovereignty today

Through manner and form restrictions, the processes and relative power in parliament have changed – even in Dicey’s lifetime through the Parliament Act 1911. He explained that the Act had not replaced parliament with the Commons, but that ‘sovereignty still resides in Parliament, i.e. in the King and the two Houses acting together’, but the Act had increased the power of the House of Commons while decreasing the power of the Lords[10]. As R (Jackson) v Attorney General shows, these restrictions may alter the power dynamics within parliament but do not alter the fact that any Act properly created through a procedure parliament properly sets cannot be invalid.[11] It may be expanded from this logic that, despite no Act of Parliament existing to create the settlement, the hierarchy of statutes previously noted is a similar procedural rule.

Parliamentary sovereignty is still a cornerstone of the constitution, but is less absolute than a century ago. EU law has become a source of law equal to an Act of Parliament protected as a ‘constitutional statute’, through the ECA. The advent of ‘constitutional statutes’, sparked by conflicts caused by the ECA, means that some statutes can be challenged by the courts. However parliament could still make or unmake any law it chose, including the ECA, so long as parliament both explicitly lists any ‘constitutional statutes’ it intends to repeal, and those within parliament have the political legitimacy and cover to bypass conventions.


7b6fb969 a925 4a4e 9340 098031c3612a

Editor in Chief, Great British Politics.

Political commentator. Degrees in Modern History and Politics and Law. Spent a lot of time on the campaign trail, for various parties. Spent a lot of time working for charities and NGOs. 

- Adam Hyde



[1] AV Dicey, Introduction to the Study of the Law of the Constitution (8th edn, Macmillan 1915) 36

[2] Statute of Westminster 1931, s 4

[3] ER Pike, Britain's Prime Ministers From Walpole to Wilson (1st edn, Odhams Books 1968) 464

[4] Pickstone v. Freemans [1989] A.C. 66 [UKHL]

[5] R (Factortame Ltd) v Secretary of State for Transport [1991] 1 A.C. 603, [UKHL]

[6] ibid

[7] Thoburn v Sunderland City Council [2002] EWHC 195 (Admin) [2003] Q.B. 151

[8] ibid

[9] *413 BH v Lord Advocate (Advocate General for Scotland intervening) [2012] UKSC 24, [2013] 1 A.C. 413

[10] AV Dicey, Introduction to the Study of the Law of the Constitution (8th edn, Macmillan 1915) 42

[11] R. (on the application of Jackson) v Attorney General - Report [2005] UKHL 56, [2006] 1 A.C. 262