April 17 2024
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In the dark: Secret evidence and the UK courts

In the dark: Secret evidence and the UK courts

At the end of last year the human rights group Reprieve together with the Tory MP David Davis and Labour MP were given permission to apply for judicial review of Prime Minister Theresa May’s decision that it was no longer necessary to establish a public inquiry to investigate allegations of involvement of UK intelligence services in torture and rendition of detainees post 9/11.

They argue that the ban on torture and degrading treatment under the European Convention of Human Rights imposes a positive obligation to conduct an independent investigation into allegations. In resisting the claim, the government seeks to rely on what is known as ‘closed material’ – in other words, secret evidence.

In the recent judgment of Reprieve v The Prime Minister [2020], the High Court was asked consider the use of such closed material. In a blow to the claimants, the High Court was persuaded the material could remain hidden. Once again, the judgment brings back into the spotlight the use of secret evidence in the English legal system; and its clash with a party’s right to know and challenge the evidence used against them.


Legal cases from World War I, through to the World War II, into peace time decisions and beyond have shown a remarkable consistency in the positions taken. Where a government official spoke the words ‘national security’ at trial, the evidence in question would usually be understood and accepted as inaccessible. This was justified on a fairly non-detailed basis of safeguarding wider security interests and what happens in the realm of national security not being a legal decision nor a justiciable matter – it was a matter of judgement and policy exercised by government. Principally, however, the concern for successive governments has been the risk that legitimately sensitive information will be released during judicial review to the detriment of national security.

Set against this backdrop, some have suggested there is an understandable tendency for the government to supress disclosure of evidence within court proceedings. To that end, the use of ‘closed material’ has become an indispensable tool for the state in court proceedings. Generally, closed material can be defined as any material that the government objects to disclosing to an opposing or relevant party; as it would be damaging to the interests of national security. The scope of closed material is wide. It may relate to minutes of discussions between government officials and the security services. Often, it pertains to sensitive or classified intelligence information/evidence gathered and relied on by the security services (MI5, MI6, GCHQ). Intelligence has naturally evolved over the years as technology has advanced, but it might include: human sources, intercepted communications, surveillance techniques, or location intelligence.

Such material has been relied upon by the state when deporting persons whose presence in the UK is deemed to not be conducive to the public good. Or where the government brings a case against an individual and the material relied upon is withheld on the premise disclosure would harm public interests or be damaging to national security. Alternatively, an individual or group wishes to bring a claim in damages against the state or judicially review its actions. In defending the claim, the government risks disclosing evidence which would threaten national security – thus, deeming it contrary to the public interest to do so.

At the same time, liberal democracy requires the administration of law to be clear and accountable. Where an intrusion into individuals’ fundamental rights occur or a person is accused of any misdemeanour, minor to major, being able to know challenge the case against them is seen a cornerstone of states governed by the rule of law. The benefits of this are not complex: it aids transparency of state decision making, it keeps us alert to the motives and intentions of those we elect and their devolved bodies, and prevents arbitrary abuses of power and resources.

Our legal system has reflected this through the development of natural justice: Audi Alteram Partem. In other words, to hear the other side or the right to be heard carries with it a right of a person to know the case which is made against him. They must know what evidence has been disclosed and what statements have been made which both support or affects them; they then must be given a fair opportunity to correct or contradict them. Lord Kerr has neatly summarised the position:

‘The right to be informed of the case made against you, is not merely a feature of the adversarial system of trial, it is an elementary and essential prerequisite of fairness … the key nature of this right and its utter indispensability to the fairness of proceedings must occupy centre stage in the debate as to whether it may be compromised … To be truly valuable, evidence must be capable of withstanding challenge.’


Approaching the use of closed material has manifested in a number of ways over the years. The English common law initially developed ‘Crown privilege’ when addressing sensitive evidence in criminal and civil court proceedings. The central feature of this was an exclusionary evidential rule which allowed the government to decide it would withhold sensitive documents; even where they might be relevant to a question or issue that is before the court. In practice, the court and non-government party were being asked to close their eyes and ignore the existence of potentially probative evidence.

The law was subsequently reformed into what we now know to be Public Interest Immunity (PII). PII is only granted, by the court, where disclosure of evidence would ‘create a real risk of serious harm to public interests’. Where PII is achieved, the closed material is omitted from proceedings entirely and has no bearing on the case whatsoever – this often causes the state to concede all or parts of their case. The government has objected to the restrictions under PII in relation to closed material and matters of national security; arguing the all or nothing choice of having to disclose sensitive information (which may threaten national security and public interests) or settle/abandon a case (it would otherwise wish to put forward) was an unsustainable position.

In 1971, under immigration law reform, the government created a specialist advisory panel, dubbed ‘the three wise men’, to review deportation decisions based on security concerns. It was described, by the at-the-time Home Secretary, Reginald Maudling, as the best possible way to reconcile the needs of national security/protection of intelligence sources with the proper rights of an individual to defend themselves. However, on closer inspection, the panel radically departed from the principles of natural justice outlined above. Little to no particulars, information, or background of the case were required to be given to an individual and they were not entitled to be represented by a lawyer at the hearing. No meaningful challenge to the allegations and evidence could take place.

After a challenge to the advisory panel procedure, at the European Court of Human Rights, the current system of Closed Material Proceedings was created. It was believed that a CMP could ‘accommodate legitimate security concerns about the nature and sources of intelligence information and yet accord the individual a substantial measure of procedural justice’.


As of today, Closed Material Proceedings (CMPs) operate in variety of legal proceedings in the English system: at immigration tribunals (Special Immigration Appeals Commission), multiple tribunals and bodies (Proscribed Organisation Appeals Commission, Pathogen Access Appeals Commission, and Employment tribunals), to help determine restrictive orders on suspected terrorists (Terrorism Prevention and Investigative Measures [TPIMS]), where the UK Treasury decides not to disclose material contrary to the public interest, in most civil legal proceedings (via section 6 Justice and Security Act 2013), and more recently they have been sanctioned in a case concerning search and seizure under the Police and Criminal Evidence Act 1984 and family care proceedings.

During the course of a case, if closed material is to be relied upon a CMP is launched. CMPs are split into ‘open’ and ‘closed’ hearings. In closed, they permit closed material to be placed before a court or tribunal in the absence of a non-government party and their legal representatives. When this happens, the non-government party is excluded from the hearing and replaced by a special advocate; a security cleared barrister who has access to the closed material. Special advocates do not directly represent the non-government party, nor are they responsible for them. They are an independent counsel whose role is to test the government’s closed material and case, ensure the interests of the excluded party have been considered, make oral submissions, and discuss disclosure with state lawyers.

At the end of hearing, where a CMP has been used, an open and closed judgment is produced. The non-government party and their representatives have no sight of the closed judgment.

The procedure is far from ideal and has been described by all corners of academia, the legal profession, and civil society as a process representing an inherent unfairness and serious incursion into common law principles of natural justice – specifically the ability of a party to know and challenge the evidence produced against them.

One obvious limitation of CMPs relates to the absence of an individual when closed material is produced and scrutinised by the court. Here, a party will not be able to directly reply to the claims made against them or make counter-arguments via their own legal representation. Despite special advocates representing the excluded party’s interests, they do not benefit from direct instructions or communication. In practice, the special advocate will have little to no communication with the excluded party after the closed material has been served. Where any communication is sought, the government is entitled to register their objections to it. Overall, the special advocate is not in a position to compensate for the role of the excluded party’s own lawyer – who would be fully informed of their clients position.

CMPs also force all non-government parties into trusting the state and security services to be fair and accurate in the presentation of closed material. This is potentially problematic depending on the nature of the material. In a Privy Council review of intercept evidence, it was concluded the information gathered was sometimes allusive, scrappy and disguised. Interpretation and translation are sometimes required as to what is being said. Greater disclosure to an excluded party might provide for an alternative explanation or context – just in case the intelligence services have wrongly understood the material. Also, special advocates might, at best, only be able to offer a tentative explanation of the evidence.

To the benefit of the CMP system, it has created a requirement whereby a ‘gist’ of the closed material has to be provided to an opposition party seeking disclosure. As a result, the party excluded from a CMP is now entitled to know: the particular issues between the parties, outlines of the closed material and its statements, and the nature and impact of particular evidence in question. They are not totally ignorant to the secret evidence that will be put before the court in their absence.

However, gisting is not universal in its application. For it to apply, Article 6 of the European Convention of Human Rights has to be engaged or an individual’s liberty (e.g. detention or a restriction of movement) has to be at risk. Where both of these requirements fall short, a party will not be entitled to a gist of the closed material and can go the whole case without knowing much of the evidence against them. As a result, potentially swathes of claims, which raise fundamental questions about government decisions or actions, will be fought, at best, blind. This also suggests our legal system is content, in some circumstances, to completely suspend an individual’s right to know the case against them.

Even in cases where a gist has been enforced, the government has adopted a minimalist approach and disclosed ‘headline allegations’, i.e., only vague outlines. The construction of gisting has left room for the state to claim that they have met their disclosure obligations without actually doing so. It is almost impossible to know whether further information could have been revealed when it is claimed to do so would prejudice or damage national security. There is also concern the government might over-rely on the excuse of ‘risk to national security’ to exempt themselves from disclosure.

In Reprieve v Prime Minister, the High Court found that Article 6 did not apply as the claimants civil rights were not directly being determined; they could not say they were themselves the subject of human rights violations and nor were any of the victims of human rights violations before the court. Neither were the claimants liberty at risk. Therefore, as the judicial review claim moves forward, the claimants will not be entitled to a gist of the Prime Minister’s closed material and will have to rely on the special advocates and their accompanying flaws.

The risk is the closed material will not receive sufficient scrutiny and the claim will fail. This could be a blow the checks and balances over executive decision making. However, we will have to wait to see how the case proceeds before coming to any conclusions.

Due to the abnormality of its procedures, the government is required to report on the frequency of CMP use. The latest figures show, between 25 June 2017 to 24 June 2018, more than 20 CMPs have been used – and that figure has doubtless grown since.

Whilst CMPs are currently held up as the best way to reconcile government secrecy with an individual’s right to know and challenge the evidence against them, the system still poses significant difficulties. A report by Amnesty International into secret evidence stressed major concern about the widespread use of a procedure which, fundamentally, denies an individual a fair trial.

It is unclear where we go from here; legal challenge to the CMP system has fallen foul at domestic and European courts. The best hope is an overdue parliamentary review, into its use recommending firmer safeguards to natural justice. As it stands, CMPs in their current form are here to stay.