Biometrics are not collected from the traveller itself, but passports are still being scanned by UK officials and these contain biometrics. Are such biometrics being (copied and) stored?
This https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/779876/borders-immigration-citizenship-system-privacy-notice.pdf sets out the approach to data capture and storage
“At the border, passenger name records data is retained for 5 years. Advance passenger information may be retained for 10 years. Arrest and detention records may be held for 6 years.”