public law,

Elgizouli v Secretary of State for the Home Department : Redefining the scope of common law constitutional rights?

By Allison Wu Apr 17, 2021


In Elgizouli v Secretary of State for the Home Department, the Supreme Court considered whether it was unlawful for the Secretary of State to authorise mutual legal assistance (“MLA”) to the United States in order to assist a criminal investigation which could lead to the imposition of the death penalty on a suspected British terrorist.1 This article first sets out the factual background and context of this case. It will then go on to examine the Court’s reasoning, particularly on the legality of the Secretary of State’s actions on the basis of common law principles.

The article will situate Elgizouli within existing jurisprudence on common law constitutional rights. In doing so, it will argue that the Court has revealed a more restrictive approach to such rights. Finally, this article will discuss how Elgizouli demonstrates that the scope of common law constitutional rights seems to be limited to procedural rights (as opposed to substantive rights).

Background of Elgizouli

In Elgizouli, the applicant’s son was suspected of involvement in a terrorist group which committed serious crimes, including the beheading of 27 men in Syria.2 In 2015, the US requested MLA – which enables the US and UK governments to share information for the purposes of criminal proceedings – with respect to an investigation into that terrorist group.3 While the Home Secretary requested the US guarantee that information provided would not be used in a prosecution that could lead to the imposition of the death penalty, the US did not provide such an assurance. Despite the lack of this assurance from the US, the Home Secretary agreed to the MLA request and supplied relevant information to US authorities.4 While witness statements had already been transferred to US authorities before the case was brought to the courts, the Supreme Court nonetheless emphasised the importance of determining the legality of the Home Secretary’s actions as “[f]urther material may be sought” 5 by US authorities.

At first instance, it was held in the Divisional Court that the Home Secretary’s actions were neither unlawful under the common law nor the provisions of the Data Protection Act 2018 (“DPA 2018”).6 However, the Divisional Court certified two questions of law of public importance: (i) whether the Home Secretary’s exercise of power to provide MLA which will facilitate the imposition of the death penalty was unlawful under the common law; and (ii) whether the Home Secretary’s exercise of power was unlawful under the provisions of the DPA 2018.7 This article will focus on the Supreme Court’s reasoning as to whether the Secretary of State’s actions were unlawful under the common law.

The Supreme Court’s reasoning

The majority held that there was no common law principle which prevented the sharing of information in an MLA request which might lead to the imposition of the death penalty. Lord Kerr was the sole dissenter on this issue and held that the common law ought to recognise that it should be unlawful to facilitate investigations by providing material which might lead to the imposition of the death penalty in a foreign country.8 Of importance is the Justices’ reasoning on the scope of common law constitutional rights and how the common law should (or should not) develop to accommodate new rights.

Giving one of the two substantive judgments of the majority, Lord Carnwath pointed out that “the death penalty […] has never attracted the attention of the common law” with recent developments coming from Parliament or the European Court of Human Rights.9 Consequently, the common law must develop “in line with the European Convention, but not beyond”.10 More crucially, as this was a case involving the facilitation of the death penalty by the transfer of information, “the development of a common law rule would have to take account of the fact that […] Parliament has recently legislated in this field, in the 2018 Act”.11 Given the highly detailed nature of data transfer rules under the DPA 2018, a common law prohibition of transfer of information in certain circumstances could not be reconciled with the statutory data protection regime.12 Lord Carnwath thus evinced a limited scope for the development of common law constitutional rights, with such rights inextricably bound up with pre-existing Convention rights and legislative frameworks.

Beyond affirming Lord Carnwath’s reasons, Lord Reed (with whom Lady Black and Lord Llyod-Jones agreed) further argued that the development of the common law must build “incrementally on existing principles”.13 In the first place, incremental development preserves “legal certainty” by ensuring that any changes to the common law are undertaken based on “established principles”.14 Furthermore, parliamentary sovereignty means that the courts should be cautious when developing the common law especially with the “procedural and institutional limitations which restrict the ability of litigation before the courts to act as an engine of law reform”.15 Against this broader principle, Lord Reed was of the opinion that the common law was not capable of supplying a right prohibiting MLA which could potentially lead to the death penalty because such a right would not be “an incremental step”.16 Drawing on constitutional and legal policy justifications, Lord Reed similarly envisioned a more restrictive role for the courts in the development of new rights under the common law.

On the other hand, Lord Kerr adopted a different approach to common law constitutional rights. Upon examining different sources of constitutional rights, Lord Kerr argued that recognising a right against the provision of information in an MLA request that could lead to the imposition of the death penalty was a “natural and inevitable extension” of the current prohibition of extradition without death penalty assurances.17 In particular, Lord Kerr emphasised that the common law should adapt to afford human rights protection in novel cases; Convention rights merely “represent a threshold protection” and cannot act as “an inhibitor to the development of the common law” in human rights jurisprudence.18 Lord Kerr thus took a more liberal approach to common law constitutional rights, with the common law being capable of independently evolving to supply human rights protection.

As Fairclough notes, Elgizouli is significant because it lays out key areas of dispute in common law constitutional rights – both relating to “the relationship between the common law and the HRA” as well as “the extent to which common-law rights can develop”.19 While Lords Carnwath and Reed arguably conceptualised a more deferential role for common law constitutional rights (both in its relationship to the Human Rights Act 1998 (“HRA”) and the development of new principles), Lord Kerr posited that the common law could dynamically develop outside the boundaries of Convention rights.


To contextualise the significance of Elgizouli, it is important to understand the developing jurisprudence on common law constitutional rights. In recent years, the courts have seemingly engendered a new approach to common law constitutional rights. In particular, the judges have stressed the vigour of the common law in supplying human rights protection. Such an approach was particularly evident in Osborn v Parole Board, where the Supreme Court stated that the HRA “does not supersede the protection of human rights under the common law or statute, or create a discrete body of law based upon the judgements of the European court”.20 Instead, the courts should develop constitutional rights in parallel to the HRA. As Elliott notes, Osborn was remarkable in that it “places common-law rights centre-stage, [with] consideration of the ECHR being treated as a secondary matter”.21 The possibility for common law constitutional rights to take precedence over and even supply stronger protection than the HRA was demonstrated in two subsequent cases. In Kennedy v The Charity Commission, the claimant argued that Article 10 of the Convention included a right to receive information from public authorities. Rejecting this argument, the Court went on to hold that there was a “common law presumption in favour of openness”22 and that a right to receive information from public authorities could possibly be supplied by the common law. Subsequently, in A v BBC, the Court emphasised that the “common law principle of open justice remains in vigour, even when Convention rights are also applicable”.23 As such, this trilogy of cases suggests that the courts have been willing to develop a richer catalogue of common law constitutional rights and that the common law could itself act as a robust defender of human rights.

At first blush, the majority’s reasoning in Elgizouli evinces a much stricter approach to common law constitutional rights and seems to contradict the Court’s liberal approach in the trilogy of cases just discussed. In Osborn, Kennedy and BBC, common law constitutional rights occupied a central position and could even take precedence over the HRA. Yet, common law constitutional rights took a backseat in Elgizouli. In Elgizouli, Lords Reed and Carnwath stated that common law constitutional rights must cautiously and incrementally develop, curtailing the capacity of the common law to evolve and provide stronger human rights protection. The question, then, is whether these positions can be reconciled; or if they cannot, perhaps it might be said that Elgizouli represents the advent of a stricter approach to common law constitutional rights.

On closer analysis, what Elgizouli reveals is that the ambit of common law rights protection has always been relatively limited in scope. In Kennedy and BBC, the right in question was a right to open justice. As Elliott argues, the Court may be particularly willing to enforce certain rights where they are “a reflection of a constitutional principle to which especial curial weight is attached”.24 This could explain why a right to open justice was particularly prized by the Court in Kennedy and BBC, as the notion of open justice is tied to rule of law considerations such as transparency and accountability.25 As such, while the common law might be generous with applying certain kinds of rights which are firmly grounded in well-established constitutional principles (such as a right to open justice), they are more reticent when it comes to recognising new types of rights (such as a right against non-facilitation of the death penalty). On this reasoning, Elgizouli sheds light on the limited normative reach of common law constitutional rights as well as the common law’s selectivity in its protection of human rights. While it might be too early to draw a conclusion on the precise scope of common law constitutional rights, it could be argued that the common law is more willing to enforce procedural rights as opposed to substantive rights, especially when those rights are linked to fundamental constitutional principles such as the rule of law.

This reading of Elgizouli might be supported by the judgement of the Supreme Court in Moohan v Lord Advocate. In Moohan, the Court considered the legality of the Scottish Independence Referendum (Franchise) Act 2013 which banned prisoners from voting in the referendum.26 Of note is the Court’s discussion of the common law position on the right to vote, which is a substantive rather than procedural right. Lord Hodge stated that the common law has not developed to “recognise a right of universal and equal suffrage from which any derogation must be provided for by law and must be proportionate”.27 In so holding, Lord Hodge observed that the right to vote has always been a statutory creation and that it would thus be constitutionally inappropriate for the common law to “override the statutory rules which determine our democratic franchise”.28 The Court’s reticence to recognise a right to vote at common law in Moohan aligns with the Court’s reluctance to extend the protection of the common law to the prohibition of supplying information in an MLA which might lead to the death penalty in Elgizouli. Ultimately, as Elliot argues, it seems that “only a subset of common law rights […] form an irreducible nucleus that may be resistant in the face of implacably incompatible primary legislation”.29

Where does this leave us? While Elgizouli does not bring us closer to drawing up a specific catalogue of rights which exist at the common law, it reminds us that common law constitutional rights are ultimately limited in breadth. While the common law might be a rigorous form of human rights protection when it comes to certain types of rights, other forms of rights are delimited from its scope. In particular, the majority in Elgizouli seems to have adopted an especially narrow conception of common law rights, with the development of such rights being constrained by statutory law and pre-existing rights enshrined in the common law. In this regard, there is a strong argument in favour of Lord Kerr’s approach, as he posits that the courts should extend common law principles to supply human rights protection in novel cases. This ties in with Fairclough’s argument that the common law should move towards a more principled approach to the identification of common law constitutional rights – by recognising that common law constitutional rights are normatively underpinned by the rule of law, this opens up the space for more rights to be protected by the common law insofar as they are underpinned by rule of law considerations.30


Ultimately, while the current scope of common law constitutional rights appears limited, we may not need to be overly concerned as things currently stand. This is because the HRA can be seen as a sufficiently rigorous way of ensuring that human rights are protected in the UK. This is especially so considering that the courts have a far-reaching interpretative duty under Section 3(1) of the HRA to give effect to Convention rights. In particular, the courts have been willing to “depart from the unambiguous meaning of the legislation” to achieve an interpretation that is consistent with the protection of human rights.31 As such, it could be argued that, where the common law is currently lacking, the HRA fills the lacuna.

Elgizouli confirms that the courts are selective when it comes to the breadth of common law constitutional rights. While the picture of human rights protection is not necessarily bleak due to the HRA, we might be more concerned if the HRA faces repeal in the future. It should be noted that the government launched an independent review of the HRA (led by Sir Peter Gross) in December 2020, focusing on the “structural framework” of the HRA instead of the substantive rights encapsulated in the HRA.32 While it seems unlikely that the HRA will be repealed in the near future, it remains to be seen how the outcome of the independent review might alter the current working of the HRA. In this sense, Elgizouli serves as a timely reminder of the importance of ensuring that the HRA has the capacity to effectively protect human rights, as common law constitutional rights are unable to offer the same rigour of protection as the HRA.

I would like to thank Professor Conor Gearty and the anonymous editors for their very helpful comments on my article. Any errors remain my own.

[1] Elgizouli v Secretary of State for the Home Department [2020] UKSC 10.

[2] Ibid [17].

[3] Ibid [25].

[4] Ibid [60].

[5] ibid [61].

[6] R (on the application of Elgizouli) v Secretary of State for the Home Department [2019] EWHC 60 (Admin).

[7]Ibid [19].

[8] Ibid [160].

[9] Ibid [194].

[10] Ibid [193].

[11] Ibid [205].

[12] Ibid.

[13] Ibid [170].

[14] Ibid.

[15] Ibid.

[16] Ibid [171].

[17] Ibid [142].

[18] Ibid [147].

[19] Thomas Fairclough, ‘Common-law constitutional rights: one step forward, two steps back?’ (2020) 79(2) Cambridge Law Journal 204, 206.

[20] Osborn v Parole Board [2013] UKSC 61 [57].

[21] Mark Elliott, ‘Osborn: The common law, the Convention, and the right to an oral hearing’ (Public Law for Everyone, 10 October 2013) «» accessed 15 April 2021.

[22] Kennedy v The Charity Commission [2014] UKSC 20 [47].

[23] A v BBC [2014] UKSC 25 [56].

[24] Mark Elliott, ‘The Fundamentality of Rights at Common Law’ in Mark Elliot and Kirsty Hughes (eds) Common Law Constitutional Rights (Bloomsbury 2020) 206.

[25] See Thomas Fairclough, ‘The Reach of Common Law Rights’ in Mark Elliot and Kirsty Hughes (eds) Common Law Constitutional Rights (Bloomsbury 2020).

[26] Moohan v Lord Advocate [2014] UKSC 67 [2]-[3].

[27] Ibid [34].

[28] Ibid.

[29] Elliott (n 24) 206.

[30] Fairclough (n 25) 316.

[31] Ghaidan v Godin-Mendoza [2004] UKHL 30 [30].

[32] Ministry of Justice, ‘Government launches independent review of the Human Rights Act’ (UK Government, 7 December 2020) <> accessed 29 March 2021.

Article by Allison Wu
LLB (London School of Econonomics and Political Science) '22