It would not be legal on the phone - unless the other party was warned first.
I'm not sure that it would be illegal face to face.
If I had been on a panel when a recording was introduced as evidence, I think we would have sought legal advice before proceeding!
all our phone calls in the out of hours GP services are recorded and the patients are told this beforehand, this is to protect both sides! Also we on occasions video consultations but this has to be done with the full consent of the patient both before AND again after the consulation - ie even after it is done it must be deleted. It also has to be made clear for what puprose the recording / videoing willbe used and who will see it. Strictly I suppose if you are recording you should offer a copy to the other person.