A legal challenge against an algorithm used to identify potential sham marriages accused the UK Home Office of discriminating against people from certain countries.

The sham marriage triage tool, which is applied to marriage applications involving someone who is not a British or Irish citizen and lacks sufficient settled status or a valid visa, identifies couples suspected of getting married just to get round immigration controls, and refers them for investigation by officials.

According to the challenge by legal charity the Public Law Project (PLP), the tool could discriminate against people from Greece, Bulgaria, Romania and Albania. The PLP also noted that Home Office secrecy about the system breaches transparency rules under the GDPR.

The move came after the UK Information Tribunal ruled in a separate ruling that “there will be some indirect discrimination” and “potential bias” in the algorithmic system the Home Office is using.