Blog: Against the criminalisation of survivors of modern slavery - the duties of the police, CPS and the Home Office under Article 4 ECHR
This blog post examines the legal duties owed by the police, the Crown Prosecution Service (“CPS”) and the Home Office towards survivors of modern slavery. It explores how key case law has clarified the scope of those obligations, especially in respect of the criminalisation of potential victims of trafficking, and considers what Article 4 of the European Convention of Human Rights (“ECHR”) requires when responding to survivors of trafficking and exploitation and how both public and private law remedies can be used to enforce this.
Legal Framework
Article 4 prohibits slavery, servitude, forced labour and it has been interpreted by the courts as encompassing human trafficking.[1] It imposes positive obligations on the state to protect survivors of modern slavery, trafficking and exploitation, to take operational measures where there is credible suspicion of exploitation and to carry out effective investigations into potential trafficking.
In order to ensure that the prohibition of modern slavery and trafficking is effective, the European Court of Human Rights has identified three positive obligations owed to victims of trafficking:
Duty to implement measures to combat trafficking
The UK and other member states have an obligation to adopt measures to combat trafficking which must be “comprehensive” and ensure “real and effective protection of the rights of victims of human trafficking”.[2] This includes penalisation and effective prosecution of any act falling within Article 4.[3]
There must also be sufficient systems in place to afford practical and effective protection against treatment falling within Article 4.[4]
Protective duty
The protective duty means that when the authorities know, or ought to know, that there is a credible suspicion of trafficking, they must take reasonable steps to protect the individual from the risk of exploitation. This obligation applies even where all the facts have not yet been fully established.[5]
The action required of the authorities can include identifying a person as a potential victim, taking steps to secure their immediate safety, ensuring access to appropriate safeguarding and support measures and assisting survivors in their full recovery.[6]
Investigative duty
Authorities also have an obligation to conduct an effective investigation where there is credible suspicion that a person has been trafficked or subjected to exploitation, regardless of whether the person themselves alleges they have been exploited.[7]
Once the matter comes to the attention of the authorities, they must investigate of their own motion. They are required to take all reasonable steps to gather evidence and establish the circumstances of the alleged exploitation. The investigation must be carried out promptly and efficiently,[8] and urgently where there is an ongoing risk of harm or an opportunity to remove a person from an exploitative situation.[9]
The criminalisation of victims of trafficking
The paramount importance of victim identification is recognised in both domestic caselaw and that of the European Court of Human Rights, even where a person has or appears to have committed a criminal offence.
Although victims of trafficking are not immune from criminal prosecution, victim status may bear directly on whether there is sufficient evidence to bring a prosecution and whether there is a realistic prospect of securing a conviction. In any event, it may also bear on whether it is in the public interest to prosecute the victim notwithstanding the alleged criminal offending, particularly given the strong public interest in combatting trafficking and protecting its victims.[10]
V.C.L and A.N v United Kingdom
V.C.L was a landmark case brought against the UK in 2021 concerning the prosecution and conviction of two children found working in cannabis factories, later identified as potential survivors of trafficking. The applicants argued that the authorities had failed to protect them after they were trafficked and had not properly investigated their exploitation resulting in an unfair trial. This case strongly reinforced that failures at an early stage after police contact can leave survivors of trafficking vulnerable to being unfairly prosecuted instead of protected. V.C.L was the European Court of Human Right’s first significant judgment addressing the prosecution of trafficking survivors for offences committed in the context of their exploitation.
Importantly, the Court found 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” (§161).
The judgment also clarified the scope of the positive obligations owed by prosecuting authorities under Article 4 and has become an important authority for those representing and advocating on behalf of survivors of trafficking and modern slavery.
Duties on the police
National police guidance[11] makes clear that where the police are aware, or ought to be aware, that an individual may be a victim of trafficking, the primary focus must be on safeguarding and supporting that person, alongside the effective investigation and disruption of those responsible for their exploitation.
Police forces, along with other statutory agencies such as Border Force and Immigration Enforcement, are designated First Responders for the purposes of the National Referral Mechanism (“NRM”)[12], meaning they are responsible for identifying potential survivors of modern slavery and human trafficking and making referrals so that people can access protection, support, and recovery services.
Officers must be trained to recognise indicators of exploitation, exercise professional curiosity, and take proactive steps to assess and reduce risk. This includes taking immediate safeguarding action where needed and making timely referrals into the NRM. Officers are expected to have the skills to build trust with survivors, ensure they feel safe and supported, help them understand the process, and provide a consistent point of contact throughout a modern slavery investigation.
The national police guidance reinforces the duty on police officers to investigate properly, requiring sensitive and structured evidence gathering in line with Achieving Best Evidence guidance, early consultation with CPS prosecutors, and the careful securing and preservation of evidence relating to trafficking or modern slavery. Intelligence checks must also be carried out to help identify and protect survivors and identify perpetrators. In more complex cases, officers are directed to specialist units, particularly where a person may also face criminal allegations as a direct consequence of their exploitation.
A lack of understanding of modern slavery within policing can have deeply harmful consequences for survivors. Where indicators of exploitation are missed, individuals may face arrest, detention and prosecution rather than protection and support. Importantly, the judgment in V.C.L also made clear that the duties of the police towards survivors are not defeated simply because a criminal defence solicitor has failed to raise trafficking at an earlier stage.
Duties on the CPS
The CPS also have a central role to play and its detailed prosecution guidance[13] reflects the UK’s obligations under Article 4 to identify, protect, and avoid the criminalisation of survivors of trafficking in specific circumstances.
Prosecutors must work closely with the police from an early stage to ensure that all reasonable lines of inquiry are pursued and that potential survivors are referred into the NRM where appropriate. Although the CPS is not a First Responder and cannot make referrals into the NRM itself, prosecutors must ensure the police properly consider referral in every case, whether the individual is treated as a victim, witness, suspect, or defendant. Prosecutors must remain alert to indicators of trafficking, even where a person is unable or afraid to disclose their exploitation, and their duties towards potential survivors continue throughout the prosecution process.
The CPS must also carefully consider whether an individual’s actions may have arisen as a consequence of their exploitation, including by considering defences such as duress and the statutory defence under Section 45 Modern Slavery Act 2015, before any charge is authorised. This requires a structured decision-making process to ensure that indicators of trafficking are properly recognised and that people are not prosecuted unfairly for conduct connected to their exploitation.
The CPS guidance sets out a clear four-stage approach which must be followed when making a decision to prosecute, including a mandatory requirement to consider whether it is in the public interest to prosecute on the basis of specific considerations including “whether the force of compulsion from the trafficking/slavery or past trafficking/slavery acting on the suspect is enough to remove their culpability/criminality or reduce their culpability/criminality to a point where it is not in the public interest to prosecute them”.
Overall, this places a clear responsibility on prosecutors to protect vulnerable survivors, prevent wrongful prosecutions, and ensure that the realities of trafficking are properly understood at every stage of a case.
Duties on the Home Office
The Home Office has a duty to identify and support victims of modern slavery and human trafficking in England and Wales through the NRM.
As referred to above, the police and other public authorities that are first responders have a statutory duty (under Section 52 of the Modern Slavery Act) to notify the Home Office when they come across potential victims of modern slavery.[14]
Specific parts of the Home Office, including UK Visas and Immigration, Border Force, and Immigration Enforcement, are also designated as First Responders. The Home Office plays a central role in the NRM system, acting as the ultimate decision-making body responsible for identifying victims of modern slavery and human trafficking through the Single Competent Authority and the Immigration Enforcement Competent Authority.
The Home Office has repeatedly made public statements about stopping smuggling gangs, and are clearly aware of the methods such gangs deploy against those seeking protection in the UK, many of whom will be potential victims of trafficking. However, research conducted by Victoria Taylor, an academic at the Oxford Centre for Borders and Criminology,[15] in collaboration with Captain Support UK, Humans for Rights Network and Refugee Legal Support has found that a significant number of criminal defendants who have been prosecuted for offences of illegal arrival and facilitating illegal arrival by piloting a small boat stated in criminal court proceedings that they had been deceived, coerced and threatened, sometimes at gunpoint, by unscrupulous gangs to procure their piloting of the boat. This has resulted in the consequential commission of a criminal offence under ss24 and/or 25 IA 1971, all for the gang’s financial gain. Yet in none of these cases have steps been taken to consider whether these individuals may also be potential victims of human trafficking and investigate the circumstances of piloting the boat as a crime of trafficking committed by the smuggling gang.
Unfortunately, it is clear that potential victims of trafficking are therefore regularly being convicted for ‘illegal arrival’ and imprisoned without ever being referred into the NRM, or having the circumstances of their potential trafficking and the link between this and their alleged offence considered.
Failure to comply with duties
In the criminal context, failures by the police, CPS and Home Office to meet their protective and investigative duties under Article 4 can have serious and life-altering consequences, including survivors of modern slavery facing prosecution and imprisonment despite indicators of exploitation or coercion, while key evidence relating to trafficking may be overlooked or inadequately investigated.
Where a person has survived human trafficking and the police and prosecutors have failed, or are failing, to meet their duties to protect and investigate, there may be grounds for bringing a judicial review challenging the failure to identify the individual as a victim of trafficking or to bring a civil claim under Article 4 ECHR.
By way of example, DPG recently represented a young Sudanese man who was forced at gunpoint to drive a small boat across the channel, yet was not referred into the NRM and was prosecuted and imprisoned for five months for illegal arrival.[16] Our client brought a claim for judicial review against the Home Office in relation to their failure to identify him as a victim of trafficking which was recently settled by consent with the Home Office conceding that they: (i) should have inquired further into our client’s account that he was forced at gunpoint to pilot the small boat across the channel and should have referred him (subject to his consent) into the NRM as a potential victim of trafficking in accordance with paragraph 4.7 of the Modern Slavery Act Statutory Guidance; and (ii) should not have been referred our client for criminal charge and prosecution without any consideration of his account and any referral to the NRM prior to consideration of a decision as to whether to charge him with immigration offences under ss24(D1) and / or 25 Immigration Act 1971. As part of this settlement, the Home Office has agreed to conduct a review of the referral form provided to their Criminal and Financial Investigation Teams when deciding whether to refer someone for criminal investigation and prosecution and to consider appropriate amendments. It is hoped that this will ensure greater protection for survivors of trafficking.
By way of another example, one of our former clients brought a successful civil claim against the police and the CPS in relation to his arrest, detention and a prolonged prosecution when he was still a child.[17] Having come to the UK as an unaccompanied child seeking asylum, he was under the care of his local authority when he was arrested. He was supported by an anti-trafficking advocate from the non-profit sector who acted as his litigation friend to support him to bring this claim. One of the claims advanced was that neither the local police force nor the CPS had an adequate system in place to identify when a suspect has a positive reasonable grounds decision or any system for notifying each other of such information.
As part of the settlement of his claim for a significant sum of damages, the local police force agreed to place markers on their systems to flag that our client is a survivor of modern slavery, that he requires specialist care and treatment and the support of an Appropriate Adult and an interpreter. It was also agreed that a case study of our client’s experience would be shared within the regional police service.
Conclusion
As discussed in our last blog post, survivors of trafficking unfortunately continue to face systemic failures in accessing protection and support in the UK. However, the anti-trafficking legal framework places clear, far-reaching and enforceable duties on the police, prosecutors and the Home Office.
In September 2025, a new pilot programme called the Independent Modern Slavery Advocate Model was launched across the UK, placing 24 Independent Modern Slavery Advocate in organisations nationwide to support adult survivors of human trafficking. Their role is to help survivors understand and access their rights and entitlements, to assist them in rebuilding their lives and to empower survivors of modern slavery to make informed choices about their own recovery.[18] This represents a welcome step towards addressing gaps in the UK’s support for survivors of trafficking and modern slavery and between the legal framework and the lived reality of survivors.
It is clear, nonetheless, that there is more work to be done, as survivors of trafficking and modern slavery are still too often treated as offenders before they are recognised as survivors. Despite clear legal duties owed by the police, prosecutors and the Home Office under Article 4, ECHR, survivors of exploitation continue to face arrest, detention and prosecution in circumstances where safeguarding and protection should have come first.
This blog post was prepared with contributions from members of our legal team including: Maja Pegler, Clare Hayes, Ralitsa Peykova and Emily Soothill. It is for general information and is not intended to be used as legal advice.
[1] Rantsev v Cyprus and Russia [2010] ECHR 25965/04, §282.
[2] Chowdhury v Greece (App No 21884/15, 30 March 2017), §87
[3] Rantsev §112
[4] Siliadin v France (2006) 43 EHRR 16 at §148.
[5] Rantsev, §§296 – 298
[6] V.C.L. and A.N. v. the United Kingdom, [2021] ECHR 77587/12 and 74603/12 para 53
[7] OOO v Chief Commissioner for the Metropolis [2011] EQHC 1246, para 164
[8] C.N. v. the United Kingdom, [2012] ECHR 4239/08, para 41, also Siliadin v. France, [2005] ECHR, 73316/01I
[9] B.B. v. Slovakia, [2024] ECHR 48587/21, para 80
[10] V.C.L. and A.N. v. the United Kingdom, [2021] ECHR 77587/12 and 74603/12, §159-161, 202.
[11] College of Policing Authorised Professional Practice - https://www.college.police.uk/app/major-investigation-and-public-protection/modern-slavery/guidance-police-responders
[12] National Referral Mechanism is a framework for identifying and referring potential survivors of modern slavery and ensuring they receive the appropriate support.
[13] CPS Prosecution Guidance on Modern Slavery and Human Trafficking Offences: https://www.cps.gov.uk/prosecution-guidance/modern-slavery-and-human-trafficking-offences-and-defences-including-section
[14] Modern Slavery Act Guidance §4.10: https://assets.publishing.service.gov.uk/media/69f3634f7c02660a84d1eb9a/Modern_Slavery_statutory_guidance_for_England_and_Wales__under_s49_of_the_Modern_Slavery_Act_2015__and_non-statutory_guidance_for_Scotland_and_Northern_Ireland.pdf
[16] Emily Soothill, Catherine Dowle and Öykü Aktaş acted for the Claimant.
[17] Clare Hayes and Chioma Nwani acted for the Claimant.
[18] The project is a collaborative effort led by Hope for Justice, British Red Cross, The Snowdrop Project and the Bakhita Centre for Research Slavery, Exploitation and Abuse, together with consultants with lived experience of modern slavery, to develop and roll out a national, accredited model of independent advocacy. More information can be found here: https://hopeforjustice.org/imsa/