King’s College London report highlights confusion over DNA evidence in UK immigration cases

A comprehensive new report by King's College London (KCL) has called for reform of DNA testing in UK immigration cases, finding that families can face unclear testing requirements, inconsistent standards between providers, significant costs and practical difficulties when attempting to establish family relationships.

The 82-page report, The Production and Interpretation of DNA Evidence in UK Family Migration Expertise, Communication and Decision-Making across Families, DNA Service Providers, Legal Representatives and the Home Office, can be downloaded here.

Research for the report was conducted through the Refugee Family Reunion Project, funded by KCL's One King's Impact Fund. It focused particularly on cases involving children seeking to join or remain with non-parent relatives under Appendix Child Relative (Sponsors with Protection) of the Immigration Rules, while also examining other immigration contexts in which DNA testing is used to verify family relationships.

The researchers collected evidence from DNA service providers, immigration lawyers, forensic experts, sample collectors and families with direct experience of the process. The study also included interviews, observations, policy analysis and a review of the market for immigration-related DNA testing in the UK.

According to the report, DNA evidence is increasingly relied upon in family reunion cases, but decision-makers and legal practitioners do not always understand the probabilistic nature of DNA results. In particular, inconclusive results may be treated as evidence against a claimed relationship, even when they indicate that the test was unable to provide a clear answer.

The researchers said that DNA testing cannot simply provide a "yes" or "no" answer about whether two people are related. The meaning of a result depends on the relationship being investigated, the people included in the test and the methods used.

The report explains: "DNA analysis occupies a distinctive position in immigration systems. While it is often perceived as objective and conclusive, DNA evidence is inherently probabilistic and context dependent. Its growing use in family reunion cases reflects broader trends toward biometric governance and technocratic forms of verification. However, the evidential weight afforded to DNA results remains unclear, and concerns persist regarding decision-makers' capacity to interpret forensic reports accurately."

It further explains: "In [refugee family reunion (RFR)] cases, DNA evidence often acquires a privileged epistemic status, being treated as more objective, reliable, or decisive than other forms of evidence such as testimony, documents, or accounts of lived family life. … The research demonstrates that this elevated epistemic status is not inherent to DNA evidence itself, but is produced through institutional expectations, infractures, legal cultures, and administrative practices. Misunderstandings of probabilistic DNA results, combined with uncertainty about how to weigh DNA alongside other evidence, can lead decision-makers to over-rely on genetic data or to treat inconclusive results as evidential failure."

The report also identified differences between DNA testing providers, particularly when families need to establish relationships beyond a standard parent-child connection. Tests designed to establish paternity may not be suitable for investigating relationships between other relatives.

Providers vary in the number and types of genetic markers they analyse, how they account for mutations and other possible family relationships, and how they present their findings. The report states that these differences are often not apparent to families and their legal advisers when selecting a service.

The report explains: "The analysis identified substantial variation between laboratories accredited by the [Ministry of Justice (MoJ)]. Differences were observed in the number of genetic markers used, the treatment of complex relationships such as half-siblings, and the handling of genetic mutations. Reporting practices also varied, with some laboratories using percentages rather than [likelihood ratios (LRs)], contributing to confusion and misinterpretation.

"A key finding is that many private DNA companies predominantly offer standard parental (parent–child) tests, even in cases involving complex kinship structures under Appendix CRP. These tests are often marketed as cheaper and quicker options, making them more accessible to applicants with limited financial resources. However, in cases involving non-parent relatives, such tests frequently result in inconclusive findings, which may then be interpreted negatively by decision-makers, or will require significant additional expense by the families as they seek a more suitable test. Importantly, this practice is not solely driven by technical limitations: even leading DNA testing companies with the capacity to conduct more complex and accurate kinship analyses often default to standard testing models with limited power, shaped by market incentives, standardised service offerings, and assumptions about what legal representatives and applicants will request, rather than by the evidential needs of complex RFR cases. The concern is whether the method and marker panel are suitable for the claimed relationship and whether their limitations are explained before the family commits to a test. DNA remains formally voluntary, although it may become difficult to decline when other evidence has been treated as insufficient."

The researchers found that public-facing websites do not always make arrangements clear, with researchers finding 23 companies and agencies were advertising DNA tests for UK immigration cases tests in June 2026, though only 12 organisations were approved by the MoJ to carry them out. In some cases, customers may not know which laboratory will analyse their samples or where the processing will take place. Samples and associated data may be sent to laboratories in Europe or the United States.

Lesley Nott, Principal Investigator and Business Manager at DNA@King's, said: "Families deserve to know which laboratories are processing their personal data and whether the tests they pay for will provide a conclusive report to support their application in order to select the right service for their needs."

The report notes that Home Office guidance states DNA evidence is voluntary and that there is no mandatory requirement for applicants to provide it. However, legal representatives and charities often take responsibility for suggesting and arranging tests. The researchers found that families seeking to strengthen their applications may feel they have little choice but to pay for testing.

Financial and practical barriers were also reported. Some families said they had borrowed money from their communities to cover testing costs, while others, including children, had to undertake long journeys or travel through unsafe areas to provide samples. Limited access to authorised sample collectors can add to these difficulties.

The researchers said the process can involve samples being routed through third countries, collection kits taking months to reach overseas locations and testing being requested after documentary evidence has been considered insufficient.

Overall, KCL said its findings demonstrated that DNA testing, despite often being regarded as objective and authoritative, is shaped by legal frameworks, institutional practices, commercial interests and differences in knowledge among those involved. Combined with testing costs and limited access to authorised sampling locations, these factors can place disproportionate burdens on refugee families and, in some cases, undermine the safeguarding and child-protection aims of family reunion routes.

The report called for sustained investment in training, clearer and more consistently applied guidance, and stronger oversight of private providers and their ownership structures, alongside greater collaboration with civil society. It said a proposed toolkit developed in collaboration with Right to Remain and other non-governmental organisations could help applicants and their advisers, but would not replace wider systemic reform. KCL said fair decision-making ultimately depended on recognising that DNA evidence did not speak for itself and that its significance depended on how the results were interpreted.

Lesley Nott commented: "We hope this report will have an impact on transparency of accreditation, standards and quality in DNA testing on the Ministry of Justice list. We recommend a toolkit be provided with accessible guidance and resources for families and their legal representatives and made available on the Home Office website alongside the recently updated DNA Policy Guidance. Knowledge exchange and updated training for decision makers will impact on smoother application processing and prompt decisions for families."