InR v. The Chancellor of Cambridge (1723) 1 Stra. 557, it was observed that “even God himself did not pass sentence upon Adam, before he was called upon to make his defence”. The importance of affording accused individuals such opportunities – and of disclosing adverse evidence in order that they may be fully exploited – is hard-wired into our criminal justice system. But there has recently been protracted litigation, culminating in the House of Lords' decision in Home Secretary v. AF (No. 3) [2009] UKHL 28, [2009] 3 W.L.R. 74, over the extent to which similar safeguards should attend the imposition upon suspected terrorists of “control orders” under the Prevention of Terrorism Act 2005 (“PTA”). Such orders may entail far-reaching consequences, including curfews, that can amount to something “not far short of house arrest”, as Lord Hope put it in AF.

The PTA requires High Court oversight of ministerial decisions to impose control orders. The court's role is to scrutinise the minister's views that reasonable grounds exist for suspecting the individual of involvement in terrorism-related activity and that the order is necessary for public protection. The PTA and rules of court made thereunder provide for the withholding from the suspect of “closed” evidence the disclosure of which would not be in the public interest; the exclusion of the suspect and his legal representative from the “closed” part of the proceedings; and his representation in such proceedings by a “special advocate” forbidden to communicate with the suspect and his representative following receipt of the closed evidence.

The central question in AF was whether it was possible, consistently with the fair hearing guarantee in Article 6(1) of the European Convention on Human Rights, for suspects to be told of allegations only in general terms, the details being treated as closed material. The fact that one appellant had simply been told that an investigation had shown him to have “a considerable jihadi pedigree” and to have taken part in “terrorist training and activities” indicates the potentially Kafkaesque nature of this procedural regime. In Home Secretary v. MB [2007] UKHL 46, [2008] A.C. 440, a majority held that the involvement of a special advocate was in principle capable of assuaging any disadvantage flowing from non-disclosure: Lord Brown thought that such a procedure would be unfair only in “wholly exceptional” cases. But an extended panel of nine Law Lords departed from that view in AF. Baroness Hale, influenced by submissions by serving special advocates, acknowledged that, in MB, she had been “far too sanguine” about their ability to represent suspects with sufficient effectiveness to render the process fair. Thus it was held that a suspect must always be given enough information to enable him to instruct his special advocate so as to facilitate an effective challenge to the case against him. This might require the provision of details that would compromise national security, requiring the Government to weigh up whether disclosure constitutes a smaller risk than the absence of a control order. Three aspects of the AF decision merit discussion.

First, an important influence was the judgment of the Grand Chamber of the European Court of Human Rights in A v. UK [2009] ECHR 3455/05 (noted [2009] C.L.J. 245). Here, a regime concerning extra-judicial detention of suspected terrorists that was procedurally very similar to the one considered in AF was held to violate due process rights. Lord Hoffmann regarded that decision as “wrong” and capable of “destroy[ing] the system of control orders which is a significant part of this country's defences against terrorism”. In contrast, several of the judges accepted that Strasbourg had got it right: Lord Hope said that “denunciation on grounds that are not disclosed is the stuff of nightmares” and that “[t]he rule of law in a democratic society does not tolerate such behaviour”. And all nine Law Lords in AF agreed that, although the Human Rights Act 1998 (“HRA”) requires them only to “take into account” Strasbourg jurisprudence, the Grand Chamber's decision was in effect determinative. Any other approach would have placed the UK in breach of its international obligations: as Lord Rodger put it, “Strasbourg has spoken, the case is closed.”

Secondly, to the extent that the decision in AF was animated by considerations other than the perceived need to fall into line with Strasbourg, it is striking that an instrumental conception of procedural fairness was dominant. In his leading speech, Lord Phillips rejected any clear distinction between “procedural fairness” and “procedure that produces a fair result”, opining that the point of fair procedures is increasing the likelihood of a just outcome. Attenuating due process rights is thus acceptable provided that it does not unduly compromise the capacity of the procedure to deliver a fair result. What, then, of evidence that is incontrovertibly inculpatory: is disclosure required when it would make no difference? According to AF it is; but the position adopted by Lord Phillips (with whose speech all but two of the other judges expressed agreement) was premised upon practical considerations such as the risk of wrongly concluding that untested evidence is unanswerable and the need for a system that is perceived to be fair. This fails to acknowledge that the worth of procedural fairness consists not only in its instrumental capacity for delivering good outcomes, but in its inherent value as a reflection of the dignity of the individual. Even if it was possible to be sure that non-disclosure would make no difference and would not undermine public confidence, there would remain a dignitarian argument – albeit not necessarily an insurmountable one – for telling the suspect what he was accused of.

Thirdly, the outcome in AF was the “reading down” of the relevant PTA provision under section 3 of the HRA – which requires legislation to be read compatibly with certain ECHR provisions whenever possible – the appellants' cases being remitted to the High Court for further consideration. Thus, when non-disclosure would be incompatible with the right to a fair trial, courts must now treat as inapplicable the requirement under the PTA to accede to Ministerial requests to withhold evidence whenever satisfied that disclosure would run counter to the public interest. Given that in the PTA Parliament spelt out in detail the procedure to be used in control order cases, this constitutes a bold use of the courts' power under section 3 of the HRA (albeit one that the Government signalled it preferred over a declaration of incompatibility under section 4). However, the option of reading down the relevant PTA provisions only existed in the first place because, as Lord Scott observed, the government had not been prepared publicly to accept that the control order system, operating as it would wish it to, “may require the curtailment of fair hearing rights and to face up to … the political consequences of that acceptance”. Of course, as a matter of domestic constitutional law, it remains possible for the Government to procure the enactment of legislation undercutting something as basic as the right to a fair hearing: but the HRA means that it must now convince Parliament to nail its colours very firmly to the mast if such legislation is to have its desired effect.