UK Home Office sham marriage triage tool

The sham marriage triage tool is an automated system developed and used by the UK Home Office 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.

System databank

Operator: UK Home Office
Developer: UK Home Office DACC

Country: UK

Sector: Govt - interior

Purpose: Detect sham marriages

Technology: Machine learning
Issue: Bias/discrimination - age, nationality

Transparency: Governance; Black box; Marketing

Risks and harms

Lawyers and civil rights advocates warn the sham marriage triage tool is opaque and unaccountable, and may be inaccurate, discriminatory, and unfair.

Nationality, age discrimination

The sham marriage screening tool has been accused of discriminating according to nationality and the age gap between partners.


According to the PLP, the sham marriage triage tool rates LOW for transparency.

System documents 🤖

Investigations, assessments, audits 🧐

Page info
Type: System
Published: February 2023
Last updated: March 2024