Women with darker skin are more than twice as likely to be told their photos fail UK passport rules when they submit them online than lighter-skinned men, according to a BBC investigation.
One black student said she was wrongly told her mouth looked open each time she uploaded five different photos to the government website.
This shows how “systemic racism” can spread, Elaine Owusu said.
The Home Office said the tool helped users get their passports more quickly.
“The indicative check [helps] our customers to submit a photo that is right the first time,” said a spokeswoman.
“Over nine million people have used this service and our systems are improving.
“We will continue to