The UK Home Office used a secretive algorithm to process visa applications, prompting lawyers and civil rights groups to warn the software could discriminate against applicants based on nationality, race or age.

The Financial Times revealed that UK authorities had been using an algorithm to process work, study and visitor visa applications but were refusing to  provide any detail about the factors used to assess risk, or how regularly the algorithm is updated because it feared this could encourage fraudulent applications.

The system had only come to the attention of immigration professionals when a group of lawyers were shown the streaming process during a visit to a visa processing centre in Sheffield.

The finding prompted lawyers and civil rights groups to express concerns that the system may disadvantage UK visa applicants by reinforcing existing societal prejudices.

It also resulted in calls for the Home Office to provide more information on how it assesses applications.