Modern slavery after DS and Brecani – what does a Conclusive Grounds Decision mean for a criminal case?

30 Jun 2021

Section 45 of the Modern Slavery Act 2015 (“the Act”) establishes a statutory defence to many offences (save those offences excluded under schedule 4 of the Act) if the person charged is a victim of slavery or trafficking. Until recently, a decision by the Single Competent Authority (part of the Home Office) that an individual was a victim of trafficking or modern slavery was enough to establish the defence, as detailed in DPP v M [2020] EWHC 3422 (Admin) (15 December 2020). A suspected victim would be referred to the National Referral Mechanism (“NRM”) by the Local Authority, the Youth Offending Team, or the Police, and the Single Competent Authority would first issue them with a Reasonable Grounds Decision, and later with a Conclusive Grounds Decision. The Conclusive Grounds Decision would be admissible as expert evidence in a criminal trial, going to the s 45 defence.

In Brecani v R [2021] EWCA Crim 731 (19 May 2021) the Court of Appeal held that Conclusive Grounds Decisions are not admissible as expert evidence because (i) caseworkers in the Single Competent Authority cannot properly be considered experts to the standard required in a criminal trial and (ii) Conclusive Grounds Decisions are not issued in accordance with CrimPR r 19 [¶ 54]. The case may be further appealed in the Supreme Court, but in the meantime practitioners must contend with the new law it has created, which will increase the rates of criminal conviction for victims of Modern Slavery.

Brecani followed DS [2020] EWCA Crim 285 (28 February 2020), in which the Court of Appeal held that deciding the facts relevant to the status of an individual as a victim of trafficking is solely and “unquestionably” a matter for the jury [¶ 40], ordering that proceedings which had been stayed as an abuse of process in the Crown Court following a positive Conclusive Grounds Decision be continued.

How can a defence lawyer still use the Conclusive Grounds Decision?


1)    The decision to prosecute


A positive Conclusive Grounds Decision may be enough to dissuade the CPS from prosecuting. Given that, after Brecani, it will not be admissible as expert evidence at trial, it is of paramount importance to wait for the outcome of the NRM referral before proceeding to trial. The CPS legal guidance on Human Trafficking, Smuggling and Slavery states:

“Where there may be consideration of charge and prosecution of vulnerable children or adults, prosecutors should consider applying the statutory defence or CPS policy on the non-prosecution of suspects who may be victims of trafficking”.

Prosecutors are instructed to take an NRM decision into account and to place some weight on it, but are not bound by it. The guidance sets out a four-stage approach to making decisions to prosecute, including a mandatory requirement to consider the public interest in prosecution where a question of slavery or trafficking is raised, including “the seriousness of the offence and any direct or indirect compulsion” and “whether a suspect’s criminality or culpability has been effectively extinguished or diminished to a point where it is not in the public interest to prosecute”.

The ECtHR held in VCL v United Kingdom 77587/12 (16 February 2021) at ¶ 161 that “given that an individual’s status as a victim of trafficking may affect whether there is sufficient evidence to prosecute and whether it is in the public interest to do so, any decision on whether or not to prosecute a potential victim of trafficking should – insofar as possible – only be taken once a trafficking assessment has been made by a qualified person”.

However, it was held in DS that there is no positive obligation not to try victims of trafficking [DS ¶ 39]. It may well be necessary to make detailed written representations to the CPS before trial setting out why it should not prosecute, including all relevant incidents and evidence to suggest that the individual is a victim of slavery or trafficking, as well as additional vulnerabilities.


Abuse of process arguments


Following DS, it is very difficult to argue that a decision to prosecute despite a positive Conclusive Grounds Decision, or without waiting for the outcome of the NRM process, is an abuse of process. In DS, it was held that a stay on grounds of abuse of process is only appropriate if a fair trial is not possible or it would be wrong to try the defendant because of some misconduct by the state in bringing about the prosecution [DS ¶ 40]. An abuse of process argument may only be successful if it is possible to show that the CPS failed entirely to take the Conclusive Grounds Decision or the NRM referral into account in making the decision to prosecute, or if, for example, they made errors of fact in relation to the NRM or the decision was Wednesbury unreasonable.


2)    Distinguishing the Conclusive Grounds Decision from that used in Brecani


According to Brecani [¶ 54], caseworkers in the Single Competent Authority cannot automatically be considered experts and so their Conclusive Grounds Decisions will not be considered expert reports. However, given that in Brecani weight was also given to the lack of compliance by the specific Conclusive Grounds Decision with CrimPR r 19, it may be that, if a Conclusive Grounds Decision contains the appropriate detail, it would be possible to distinguish it from the decision examined in Brecani. Note the requirements of CrimPR r 19.4 that the Conclusive Grounds Decision must:

(a) give details of the expert’s qualifications, relevant experience and accreditation;

(b) give details of any literature or other information which the expert has relied on in making the report;

(c) contain a statement setting out the substance of all facts given to the expert which are material to the opinions expressed in the report, or upon which those opinions are based;

(d) make clear which of the facts stated in the report are within the expert’s own knowledge;

(e) where the expert has based an opinion or inference on a representation of fact or opinion made by another person for the purposes of criminal proceedings (for example, as to the outcome of an examination, measurement, test or experiment)—

(i) identify the person who made that representation to the expert,

(ii) give the qualifications, relevant experience and any accreditation of that person, and

(iii) certify that that person had personal knowledge of the matters stated in that representation;

(f) where there is a range of opinion on the matters dealt with in the report—

(i) summarise the range of opinion, and

(ii) give reasons for the expert’s own opinion;

(g) if the expert is not able to give an opinion without qualification, state the qualification;

(h) include such information as the court may need to decide whether the expert’s opinion is sufficiently reliable to be admissible as evidence;

(i) contain a summary of the conclusions reached;

(j) contain a statement that the expert understands an expert’s duty to the court, and has complied and will continue to comply with that duty; and

(k) contain the same declaration of truth as a witness statement.

A very detailed and CrimPR r 19 compliant Conclusive Grounds Decision might be admissible as fresh evidence for an appeal, or as evidence in trial.


3)    Reliance on the material underlying the Conclusive Grounds Decision


While the Conclusive Grounds Decision itself will not be admissible at trial, if the tribunal of fact is presented with the material underlying the Conclusive Grounds Decision, it may well be enough to satisfy the s 45 defence. Similarly, such evidence could be presented as fresh evidence on appeal.


4)    Instructing another expert


While evidence from the Single Competent Authority was deemed inadmissible in Brecani, it was held at ¶ 58 that “There can be circumstances in which a suitably qualified expert might be able to give evidence relevant to the questions that arise under the 2015 Act, which are outside the knowledge of the jury, particularly to provide context of a cultural nature”. This leaves open the question of who is a suitably qualified expert. In Brecani, reliance was given at ¶ 44 to the words of Lawton LJ in R v Turner [1975] QB 834 D to E:

“An expert’s opinion is admissible to furnish the Court with scientific information which is likely to be outside the experience and knowledge of a judge or jury. If on the proven facts a judge or jury can form their own conclusions without help, then the opinion of the expert is unnecessary… The fact that an expert has impressive scientific qualifications does not by that fact alone make his opinion on matters of human nature and behaviour within the limits of normality any more helpful that that of jurors themselves; but there is a danger that they may think it does.”

And so, expert opinion is admissible only if it is relevant to a matter in issue, the witness is competent to give the opinion, and it is needed to provide the court with information likely to be outside the court’s own knowledge and experience [Brecani ¶ 44]. Additionally, it must comply with the formal requirements of CrimPR r 19.

For the expert to be competent to give the opinion, it is likely that they should have expertise in the specific area of trafficking or slavery suffered by the individual charged with an offence, be that academic expertise or experience working directly with victims of that kind of trafficking or slavery. As to what qualifies as information likely to be outside the court’s own knowledge and experience, this will likely be quite wide when it comes to trafficking and slavery. The court in Brecani specified “context of a cultural nature” but did not exclude the possibility of other aspects. Moreover “context of a cultural nature” is itself wide in scope.




Establishing a defence under s 45 of the Act has been made very difficult by the decisions in DS and Brecani. Given how much weight is given to the Conclusive Grounds Decision in the immigration context – it is considered, unsurprisingly, conclusive – it is surprising that the criminal courts have taken such a different line. This is especially so when in many other ways those charged with criminal offences are afforded much greater protection in accessing a fair trial than those navigating the immigration system – for example, benefitting from much stricter requirements for detention without charge or admissibility of bad character evidence. If Brecani reaches the Supreme Court, those appealing the decision will need to contend with the fact that Conclusive Grounds Decisions do not routinely comply with the requirements for expert witness statements in CrimPR r 19. In particular, the writer is not named but is a faceless state official. Could the Home Office be persuaded to change the Conclusive Grounds Decision format to comply with CrimPR r 19?

The underlying context is, of course, the use of the s 45 defence and the Conclusive Grounds Decisions in establishing defences for youths involved in drugs, particularly “County Lines” drug smuggling, or other gang related offences – something that certain arms of the state are eager to restrict.


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