The theory and practice of the proportionality test in legislative decision-making

Savukynas, E. (2026) The theory and practice of the proportionality test in legislative decision-making. PhD thesis, University of Reading. doi: 10.48683/1926.00128863

Abstract/Summary

The doctrine of proportionality is central to human rights adjudication, yet its role in legislative decision-making is underexplored. This thesis examines the desirability of employing proportionality in legislative processes, combining theoretical analysis with case studies from the United Kingdom’s weak-form model of rights protection. It first considers proportionality in judicial review, assessing its advantages and drawbacks for the judiciary, before developing a theory of why legislatures in certain jurisdictions adopt proportionality reasoning, linked to interbranch power dynamics. It then considers the normative case for proportionality and argues it is most compelling under a deliberative model of democracy. As an expression of the ‘culture of justification’, it promotes transparency and accountability. Its structured subtests provide a systematic way to articulate and evaluate justifications for laws, ensuring reasoning is explicit and accessible. These features are particularly valuable in law-making, where legitimacy depends on transparency, deliberation, and accountability. Empirically, the thesis analyses the Nationality and Borders Bill and the Police, Crime, Sentencing and Courts Bill. It distinguishes between lawmakers’ uses of implicit proportionality (reasoning resembling proportionality without explicit reference) and explicit proportionality (direct invocation of the doctrine). The latter, intuitively, seems preferable, but in practice it was found often to operate rhetorically, at times undermining rights protection. The case studies confirm that proportionality’s value depends on structured application: when detailed, it strengthens transparency and deliberation; when superficial, it obscures real motivations. To realize its potential, legislatures must adopt mechanisms supporting structured proportionality review and move beyond superficial engagement. The thesis considers reforms including enhanced judicial power and institutional change within UK Parliament, ultimately arguing that reforms to the House of Commons through electoral adjustments, pre-legislative scrutiny, and committee reform offer the most promising path. Such changes would amplify human rights considerations, empower Parliament, and embed structured proportionality within legislative practice, advancing deliberative democracy.

Item Type	Thesis (PhD)
URI	https://centaur.reading.ac.uk/id/eprint/128863
Identification Number/DOI	10.48683/1926.00128863
Divisions	Arts, Humanities and Social Science > School of Law
Date on Title Page	November 2025
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