Held, appeal dismissed. (1) While it would have been easy for the drafters of article 597 to replicate the “proportionality bar” as it was found within section 21A of the Extradition Act 2003, with an exclusive focus on specified matters (seriousness of the conduct; likely penalty; possibility of less coercive measures), that was not what the language and structure of article 597 did. Instead, article 597 required the executing judicial authority to decide whether the surrender of the person was necessary and proportionate and, in doing so, to take into account both the rights of the requested person and the interests of the victims, having regard to three further specified matters, namely (i) the seriousness of the act, (ii) the likely penalty that would be imposed and (iii) the possibility of a state taking measures less coercive than the surrender of the requested person, particularly with a view to avoiding unnecessarily long periods of pre-trial detention. The article 597 “principle of proportionality” was to be applied in a different way to different kinds of cases and, in particular, accusation and conviction warrant cases were to be treated in different ways as the second and third specified matters were otiose in the context of a conviction warrant. The features identified in article 597 as informing the application of the “principle of proportionality” were not exhaustive. Instead, article 597 described a single, overall evaluation of necessity and proportionality, identifying a general test (necessity and proportionality) and a number of identified relevant considerations which fed into the consideration of that test, rather than providing an exhaustive and prescriptive set of features. Article 597 did not require “determinative weight” to be given to the features to which regard was to be had. In particular, it was not framed so as to require a narrow and distinct enquiry into the seriousness of the act, the outcome of which might itself provides a basis for discharge of the requested person, nor did it require special weight, or determinative weight, to be given to the lesser or greater “seriousness of the act” (paras 34–37).

(2) There was no conflict or incompatibility between the article 597 “principle of proportionality” and the “conventional” balancing exercise under article 8 in an extradition case. Rather, there was a clear consistency and congruence. Article 597 of the TCA did not prescribe anything which the article 8 balancing exercise would fail to deliver. The word “necessary” in article 597 reflected the language of article 8 itself (“necessary in a democratic society”), and, similarly, the ”proportionate” and the phrase “principle of proportionality" reflected the proportionality principle which was the recognised governing test for evaluating the justification in article 8 terms for the act of extraditing the requested person, given the interference with private life (and frequently family life) which extradition would entail. While in an article 8 case the rights of the requested person were naturally at the forefront, including the rights to respect for private life and family life, third party rights (for example the partner or child) were also highly relevant and their principled protection was consistent with the language and structure of article 597, which did not say that the only relevant rights were those of the requested person. Likewise, the nature of the interests of any victims of the requested person's criminal conduct (in a conviction warrant case) or alleged criminal conduct (in an accusation warrant case) were part of the familiar “public interest” considerations in favour of extradition. Similarly, under a conventional article 8 balance sheet exercise the extradition court would, in a conviction warrant case, have regard to the seriousness of the act as characterised and reflected in the sentence which had been imposed by the issuing state. The article 8 proportionality balancing exercise was thus conducted taking into account and having regard to the matters identified in article 597, to the extent that they were relevant to the nature of the warrant and on the facts and circumstances of the case. Accordingly, the relevant domestic statutory provision, as applicable through section 21(1) of the 2003 Act, achieved compliance with the principle of proportionality described in article 597 of the TCA (paras 37–29).

Per curiam. Given the consistency of section 21 of the 2003 Act with the TCA it is not necessary to determine whether a principle of “conforming” interpretation applies. However, the better view is that it would be proper for the court to adopt a “modified” interpretation of a provision of domestic legislation in order to avoid patent incompatibility with some necessary feature of the TCA (para 40, 41).