Patient Proof of ID

We don't ask to see ID. But I too am not sure if we should be doing so. Because they ask you for ID when you register at a GP surgery, some patients ask if I need to see ID.

Does anybody know the legal situation regarding seeing proof of identification when registering as a new patient.
I recently rand the GDC asking the same question and their answer was "they have no comment on this".
I also rang CQC and asked the same question and their answer was" that is something that we do not look at".