The sham marriage triage tool is an automated system developed and used by the UK government to detect fake marriages and civil partnerships in which couples get married to avoid immigration law rather than because they have a genuine relationship.

The system was discovered to have been covertly introduced in March 2015 as part of a 'hostile environment' immigration policy. A machine learning-based triage system was introduced in April 2019.

The AI algorithm assesses couples against eight risk factors, including the age difference between the couple and any shared travel history, and divides them into 'red' and 'green' light categories.

A red light referral can put a person’s immigration and visa status at risk, and may lead to an investigation, legal action and deportation.

Transparency and accountability 🙈

The UK's sham marriage triage tool is seen to suffer from multiple transparency and accountability limitations.

• Public information. The public has not been consulted or informed about the use of this system, despite its potential for life-changing decisions. The details of how the system operates have not been made public.

• Independent oversight. The algorithm seems to have been developed and deployed without any independent oversight or external review, raising concerns about accountability and potential unchecked biases.

• Data access. Without access to the underlying data and the eight screening criteria used by the system, it is difficult to confirm whether the system is discriminatory.

• Risk management. The Home Office has refused to disclose all of the "risk factors" used by the algorithm to assess cases. This lack of transparency makes it impossible to independently evaluate whether these factors contribute to unjustified indirect discrimination.

• Human review. There is uncertainty about whether there is always a human/manual review of "fail" cases that trigger an investigation. This lack of clarity raises questions about accountability in decision-making.

• Legal opacity. The PLP's legal challenge claims that Home Office secrecy about the system breaches transparency rules under the GDPR.

• FOI requests. The Home Office has rejected Freedom of Information requests for more detailed information about the system's impact on different nationalities.