I don't know why private COVID test providers issuing fit-to-fly certificates (rapid antigen) are allowed to ask their customers to send an unobstructed, unblurred photo of a passport next to the test. It feels like a huge identity theft risk - there are hundreds of these companies in the UK alone and I bet no-one controls them. They are not established companies, almost all of them emerged in 2021. This is not really safe, to send them passport photos.
What can I do to protect myself from identity theft if I need to do such a test and can't do it in person within the time-frame given by the country I'm travelling to (24 hours before crossing the border)?
and I bet no-one controls themNot necessarily. The government provides a list of authorised providers so only use the firms in the list. – DumbCoder Dec 20 '21 at 10:37