Public Law for Everyone

Now-published government witness statements submitted to prosecutors in the China espionage case cast only limited light on what happened. In this post, I outline six key questions that remain to be answered by government ministers and the Crown Prosecution Service

Under intense political pressure to do so, the Prime Minister announced in the House of Commons on Wednesday that he would publish in full the three witness statements submitted by the Deputy National Security Adviser to the Crown Prosecution Service in connection with the collapsed China espionage case. They can be now be found on the government’s website. The statements were respectively submitted in December 2023, February 2025 (not February 2024 as the statement itself says) and August 2025. Thus, the first statement was published under the previous, Conservative government, while the latter two statements were published under the present, Labour government.

A helpful summary of the witness statements, which I will not attempt to repeat here, can be found on the BBC News website. Nor will I attempt to summarise the background to the current furore, which I addressed in two previous posts (here and here). Rather, I will focus in this piece on what I consider to be six questions that remain outstanding following publication of the witness statements, bearing in mind that the key legal issue arising from the Official Secrets Act 1911 and the Court of Appeal’s Roussev judgment interpreting the Act, is whether a jury could be satisfied that China constituted a threat to UK national security when the relevant events occurred in 2021–23.

1. Why did the Prime Minister rely on the previous government’s failure to ‘designate’ China?

Speaking to reporters last week, the Prime Minister said:

‘What matters is what the designation [of China] was in 2023, because that’s when the offence was committed…’

In my first post on this topic, I argued that the concept of designation was a red herring: first, because no formal, binary categorisation exists of states that respectively do and do not constitute national security threats; and, second, because even if such a categorisation existed, a criminal court would still require evidence to justify the inclusion of a country within a list of those that are threats to national security. While this point might appear technical, it is important because, notwithstanding the way in which the current government’s narrative has evolved over the past week, there has been a consistent attempt to give an impression that matters were fixed by the previous government’s ‘categorisation’ of China. However, the Deputy National Security Adviser’s witness statements make it abundantly clear that it is well understood within government that that is not how the Official Secrets Act works and that what is required is a qualitative assessment of the threat posed by China. This invites the question: Why did the Prime Minister and other ministers convey the contrary impression on multiple occasions?

2. Why does the third witness statement refer to the current government’s China policy?

The second question follows from the first. Ministers have been implacable in their insistence that their hands are tied by the previous government’s evaluation of the threat posed by China. I have explained in previous posts that that is not the case, and that there is nothing in the relevant legislation or case law that would prevent the current government from providing evidence of its own assessment of the threat posed by China in 2021–23. That the current government’s hands are not tied in the way that ministers, including the Prime Minister, have repeatedly asserted becomes clear when paragraph 8 of the third witness statement, issued in August 2025 under the current government, is considered:

It is important for me to emphasise, however, that the UK Government is committed to pursuing a positive relationship with China to strengthen understanding, cooperation and stability. The Government’s position is that we will co-operate where we can; compete where we need to; and challenge where we must, including on issues of national security.

The inclusion of this paragraph demonstrates that ministers were wrong to assert that they could not include in witness statements in this case information about the current government’s, as distinct from the previous government’s, position. Why did ministers insist they were bound by the previous government’s assessment of the risk posed by China when the CPS was in fact provided with information about the current government’s China policy? And given that some information about the current government’s position was included, does that not imply that the current government could have gone further in terms of describing its assessment of the China threat in 2021–23 but that it chose not to do so? The latter point links closely to a point, addressed under question five below, concerning the respective roles of ministers and the Deputy National Security Adviser in this context.

3. Why did the CPS think it lacked sufficient evidence to proceed?

In none of the witness statements does the Deputy National Security Adviser describe China as an ‘enemy’ (which is the relevant term used in the Official Secrets Act) or say in terms that ‘China was a threat to national security in 2021–23’ (the Court of Appeal having defined ‘enemy’ as including states that threaten UK national security). However, to conclude on that basis that there was insufficient evidence to proceed with a prosecution implies a highly formalistic reading of the witness statements.

Those statements are replete with language that makes clear the scale and gravity of the threat China poses to the UK. We are, for instance, told (in language echoing the 2023 Integrated Review Refresh) that China is ‘an epoch-defining and systemic challenge with implications for almost every area of government policy and the everyday lives of the British people’. The Deputy National Security Adviser also writes that China conducts ‘large scale espionage operations against the UK to advance the Chinese state’s interests and harm the interests and security of the UK’, and that China’s espionage operations ‘threaten the UK’s economic prosperity and resilience, and the integrity of our democratic institutions’.

In explaining its decision to drop the case, the CPS said that its decision was made on the basis of lack of suitable evidence. The evidential test set out in the Code for Crown Prosecutors is as follows:

Prosecutors must be satisfied that there is sufficient evidence to provide a realistic prospect of conviction against each suspect on each charge. They must consider what the defence case may be, and how it is likely to affect the prospects of conviction. A case which does not pass the evidential stage must not proceed, no matter how serious or sensitive it may be.

It is important to note that this does not require prosecutors to be certain that a jury would convict or to be confident that it would do so. It merely requires prosecutors to be satisfied that there is a ‘realistic prospect’ of conviction. It is difficult to see why that threshold was not met. This raises the question: Why did the CPS decide that the evidential test was not met, given the detailed nature of the Deputy National Security Adviser’s witness statements that make clear the nature and gravity of the threat posed by China?

4. What did the CPS think was the effect of the Roussev judgment?

In his recent letter to the chairs of two parliamentary select committees, the Director of Public Prosecutions said:

It is the legal responsibility of the CPS to independently assess the evidence in every case. That responsibility is an ongoing obligation throughout the life of a case. I am satisfied that the decision to charge this case in April 2024 was correct. This was on the basis of where the law stood at that time in relation to the requirements of the Official Secrets Act 1911. Some weeks later, a High Court decision (R v Roussev and others 2024) ruled that “enemy” for the purposes of the 1911 Act includes a country which represents at the time of the offence, a threat to the national security of the UK. In the light of this new judgment, it was considered that further evidence should be obtained.

It is implicitly clear from the third witness statement that, following the Roussev judgment, the CPS decided it wanted the Deputy National Security Adviser to address more directly the threat posed by China to UK national security. But along with the point made above — that it is unclear why the CPS was not satisfied by the third witness statement (read with the first two) — further questions arise. What did the CPS and the DPP think the Roussev judgment’s effect was? In particular, did they, as the language of the DPP’s letter quoted above implies, think that, rather than loosening the definition of ‘enemy’, it somehow raised the threshold? If, as many commentators think, Roussev lowered the threshold, why did the CPS decide that the totality of the evidence it had by August 2025, under a looser legal test, was insufficient, when it had previously concluded in early 2024 that, under a stricter test, it already had sufficient evidence?

5. Was the Deputy National Security Adviser given an opportunity to address CPS concerns about his evidence?

In his recent letter, the Director of Public Prosecutions, after appearing to refer to the Roussev case that widened the definition of ‘enemy’ so as to include states that threaten UK national security and stating that this required further evidence to be obtained, said:

Efforts to obtain that evidence were made over many months, but notwithstanding the fact that further witness statements were provided, none of these stated that at the time of the offence China represented a threat to national security, and by late August 2025 it was realised that this evidence would not be forthcoming. When this became apparent, the case could not proceed. This was a professional assessment made by CPS lawyers experienced in prosecuting national security and espionage cases, applying the Code for Crown Prosecutors.

It is impossible to infer from the witness statements alone what happened after the third and final statement was submitted to the CPS. However, at some point between August and September 2025, the CPS concluded that that witness statement, in combination with the first two, was insufficient. When the CPS concluded that the first and second witness statements were insufficient, the Deputy National Security Adviser was asked to provide further evidence, as he did by way of his second and third statements, which raises the question: When the CPS concluded that the three witness statements combined were insufficient, was the Deputy National Security Adviser given an opportunity to address the CPS’s concerns about remaining perceived evidential gaps? And if not, why not?

6. If Ministers were wholly uninvolved, why were they wholly uninvolved?

Ministers, including the Prime Minister, have repeatedly asserted that they — along with the National Security Adviser — were uninvolved in relevant matters. For instance, the Security Minister told the House of Commons:

[O]n the question of what Ministers knew about the Government’s interactions with the CPS, Ministers were aware that evidence was being provided by the deputy National Security Adviser to the CPS as it built a case for prosecution, as was first agreed under the previous Government. Ministers and special advisers did not take decisions about that evidence and they were not cited in the contents. The deputy National Security Adviser was given full freedom to provide evidence without interference, as was the case before the general election.

And the Prime Minister told the House that:

Under this Government, no Minister or special adviser played any role in the provision of evidence. I cannot say what the position was of the previous Government in relation to the involvement of Ministers or special advisers.

While it is clear that the Deputy National Security Adviser, as the person giving the evidence, is responsible for his own evidence, it is also the case that he was giving evidence as to the positions of the respective governments he served. As noted above, this includes the current government, notwithstanding ministerial protestations to the effect that its own position was irrelevant. If, as is clear, the Deputy National Security Adviser’s statements in part amount to a distillation of the government’s stance and policy in respect of China and the threat it poses, questions as to the content of that stance and policy are ultimately matters for which ministers are constitutionally responsible. Indeed, the notion that the witness statements amount to nothing more than the product of a technocratic exercise is contradicted by paragraph 8 of the third statement, quoted above, which closely mirrors the following language found on page 120 of Labour’s 2024 election manifesto:

After 14 years of damaging Conservative inconsistency over China, Labour will bring a long- term and strategic approach to managing our relations. We will co-operate where we can, compete where we need to, and challenge where we must. We will improve the UK’s capability to understand and respond to the challenges and opportunities China poses through an audit of our bilateral relationship. We will always act in our interests and defend our sovereignty and our democratic values. We will stand with and support members of the Hong Kong community who have relocated to the UK.

All of this underlines the point that while the Deputy National Security Adviser was, of course, responsible for his own evidence as a witness, his evidence was, at least in part, describing the stances and policies of successive governments — matters for which ministers, not officials, are responsible. This, in turn, undermines the strenuous ministerial attempts that have been made to convey the impression that it was appropriate for this whole affair to be handled within an official, technocratic bubble. So too does the following frank comment made by the Prime Minister’s spokesperson in response to a media question about why references were made in the third witness statement to the current government’s policy:

Civil servants are rightly expected to reflect the policy of the government today in their work, and this is no different, but it provides context to earlier witness statements.

This makes it perfectly clear that the Deputy National Security Adviser’s witness statement was, as it ought to have been, made within a wider policy framework determined by the government.

Where does this leave us? Points advanced about the independence of witnesses in the context of live cases are a distraction from the distinct but related fact that in this case, the witness statements in part concerned matters of government position and policy that, are ought to be, for ministers. In such a context, a distinction must be drawn between the independence of the witness in terms of the statement itself and the process of determining relevant issues of position and policy that are described in the witness statement. The question therefore remains: If Ministers, and the National Security Adviser, were wholly uninvolved in this process, why were they uninvolved, given that the process of producing these witness statements entailed, in part, making determinations about and representing matters of government position and policy for which ministers, not officials, are constitutionally responsible?