High Court Provides Guidance on Article 3 Operational Duty and the Illegal Migration Act 2023 (25 February 2026)

The High Court has handed down an important judgment in R (MXV) v Secretary of State for the Home Department [2026] EWHC 251 (Admin).  The case provides the first substantive guidance on how Section 12 of the Illegal Migration Act 2023 interacts with the long-established Hardial Singh principles. The case also builds on existing case law concerning the Article 3 operational duty owed to immigration detainees with HIV.

Case Background

MXV, a Zimbabwean national previously recognised as a refugee in the UK, was detained in March 2024. At the time of his detention he was street homeless and had been diagnosed with both HIV and paranoid schizophrenia. He had not been taking his antiretroviral medication for some time prior to his detention.

Having failed to receive or respond to deportation and cessation notices, largely as a result of being unrepresented, deportation and cessation orders were made against him in November 2022. The Home Office subsequently detained him under immigration powers in March 2024 with removal directions set for 19 March 2024.

During his detention, MXV requested that his antiretroviral and psychiatric medication be restarted. The removal directions were deferred due to uncertainty over his medication. A month into his detention, a HIV specialist confirmed that MXV had a dangerously high viral load, that the virus may have developed resistance to standard treatment, and that he was not fit to travel. Despite this, MXV was not provided with his HIV medication until 3 May 2024, 52 days into his detention. He was eventually released on 19 June 2024, following an order for judicial review and interim relief. In total, he was detained for 100 days.

Following his release, MXV's condition significantly improved and he successfully challenged the revocation of his refugee status.

The Article 3 Operational Duty

The Court reaffirmed the operational duty under Article 3 ECHR, as previously articulated in CSM v SSHD [2021] EWHC 2175 (Admin). Where the state detains an individual, it assumes responsibility for their welfare and safety. This obligation, to take all reasonable steps to avoid a real and immediate risk of substantial and significant harm, is particularly stringent in relation to those who are especially vulnerable due to physical or mental health conditions.

The Court confirmed that a claimant does not need to show that a breach of the operational duty itself constitutes an Article 3 violation.

Importantly, the Court rejected the Home Office's argument that the operational duty was not engaged simply because MXV had not been taking his medication prior to detention. By placing MXV in detention, the state assumed responsibility for his care, regardless of his pre-detention compliance.

However, on the specific facts, the Judge found that the operational duty had not been breached, distinguishing the case from CSM on the basis that MXV had not been adherent to his medication prior to detention, and finding that the Home Office had taken appropriate steps once he was detained, with delays attributed primarily to difficulties in securing HIV clinic appointments rather than a systemic failure.

A Practical Framework for HIV Cases in Detention

The judgment provides a clear framework for how the Home Office must approach the detention of individuals with HIV, which will be valuable for practitioners advising detained clients:

Where a detainee is adherent to their medication prior to detention, the Home Office must take all reasonable steps to maintain that access from the outset. Where a detainee has an active presumption of treatment but has not been fully compliant, reasonable steps must be taken to provide access and support compliance. Where a detainee has not taken treatment for some time, all reasonable steps must be taken to offer a referral to recommence medication, and those steps must be taken expeditiously.

In all cases, the Home Office must first take reasonable steps prior to detention to ascertain whether the individual has HIV.

The Policy Challenge

MXV also challenged the Home Office's current policy for managing HIV in the detained estate, arguing it was inadequate following the findings in CSM. The current policy sits within the Adults at Risk framework and contains one reference to HIV.

Whilst the Judge acknowledged that the limited express reference to HIV gave him considerable pause for thought, he ultimately declined to find a systems-level breach of Article 3, linking his conclusion closely to his finding that the Home Office had adequately managed MXV's medical needs on the specific facts. The judgment leaves open the possibility that a stronger set of facts, where individual failures are clearer, could lead to a different outcome on the systemic question.

The Illegal Migration Act and Unlawful Detention

Of particular note for practitioners is the Court's treatment of Section 12 of the Illegal Migration Act 2023, which amended the test for detention by placing greater weight on the Secretary of State's own opinion as to whether removal within a reasonable period is achievable, rather than the Court's independent assessment.

The Judge's conclusions on this point will be reassuring. He found that the changes introduced by the IMA are "likely to have a more muted practical impact than at first sight might appear." The Court rejected the proposition that the Secretary of State is now the primary decision-maker on detention, confirming that the Court retains a meaningful supervisory role. Critically, where Article 5 ECHR is relied upon, as it should be in any challenge to the lawfulness of detention, the Court remains entitled to assess all relevant factors for itself, in the same way it previously assessed compliance with the Hardial Singh principles. The IMA does not remove that protection.

Applying this approach, the Judge found that MXV had been unlawfully detained between 1 and 19 June 2024.

What This Means for Detained Clients

This judgment is a significant addition to the case law on immigration detention and should be considered by anyone representing individuals who are detained, particularly those with serious medical conditions. The Court's approach to Article 5 and the Illegal Migration Act confirms that detention challenges remain viable and that the Courts will not simply defer to the Secretary of State's assessment. When seeking interim relief, practitioners should be confident that the Court will exercise its own judgment rather than treating the Home Office's opinion as determinative.

Duncan Lewis Solicitors has extensive experience representing clients in immigration detention, including judicial review and unlawful detention claims. If you or someone you know has concerns about the lawfulness of immigration detention or the provision of medical care in detention, please contact our Public Law and Immigration teams for advice.

Read more about this on Bailii, Administrative Court Blog and Free Movement.

About Jamie Bell

Jamie Bell is a Solicitor in the Public Law and Immigration Department at Duncan Lewis Solicitors, where he has built an exceptional reputation in complex, high-profile cases since joining the firm in 2014. His extensive experience in challenging immigration detention, particularly on behalf of vulnerable clients including those with serious medical conditions, psychological conditions, and histories of torture, makes him exceptionally well-placed to advise on cases engaging the principles set out in R (MXV) v SSHD.

About Ben Nelson

Ben Nelson is a Senior Caseworker in the Public Law team at Duncan Lewis, working under the direct supervision of Jamie Bell. Since rejoining the firm in 2023, Ben has been involved in some of the most significant public law challenges in the immigration field, including successful judicial review proceedings on behalf of asylum seekers detained on Diego Garcia and the landmark concession secured for over 6,000 individuals whose asylum claims had been indefinitely paused for Rwanda removal purposes.

About Duncan Lewis

Duncan Lewis has extensive experience representing clients in immigration detention, including in judicial review proceedings, unlawful detention claims and challenges involving the Article 3 operational duty. If you have a case that engages any of the issues covered in this judgment, please do not hesitate to contact the Public Law team for further guidance.