A good modern example of McHagg's "Declared Convention"¹ can be seen in the Sewel Convention. During the enactment of the Scottish Act 1998, concerns were raised about preserving Parliament's legislative authority over matters delegated without the consent of the Scottish Parliament.²

To address these concerns, the British Government issued a memorandum, stating that it would follow the convention that the British Parliament generally does not legislate on delegated matters except with the consent of the delegated legislature.³ This new constitutional agreement embodies principles of democracy.

However, being able to declare a convention does not make it binding. McHagg states, "The obligatory nature of traditional rules is not only demonstrated but actually constructed," distinguishing between evolved and declared conventions. Evolved conventions are established rules with a history of compliance, whereas declared conventions are merely suggestions and serve as a form of soft law to influence constitutional behavior rather than to create binding norms.⁴ It is noted that a declared convention is only a proposed rule and requires subsequent conformity to acquire binding force.

Therefore, it is evident that conventions are inherently more flexible than laws because retrospective or forward evidence of use is required for a convention to be considered binding, whether evolved or declared.⁵ However, would it be relatively faster and easier to implement constitutional principles through law, as years of conformity are not necessary to establish valid laws?

References

1. McHarg, “Reforming the United Kingdom Constitution: Law, Convention, Soft Law” (2008) 71(6) Modern Law Review 853, 856
2. The legislative supremacy of the Westminster Parliament, even on devolved matters, is expressly preserved by s.28(7) of the Scotland Act 1998
3. Memorandum of Understanding and Supplementary Agreements Between the United Kingdom Government, the Scottish Ministers, the Cabinet of the National Assembly of Wales and the Northern Ireland Executive Committee (2001), Cm.5240, para.13
4. Ibid
5. Ibid