Stephen Wilson wrote:

I think the confusion is down to way it's been described. Dr Who never went
out live, but due to the way it was recorded it was very much like a live
show. Scenes were recorded in order, there was little opportunity for
retakes, etc. So although it was all committed to tape before transmission,
the process for the actors, stage hands, etc. probably didn't differ much
from a show that did go out live.

Plus, I guess at the time that VT equipment and consumables were pretty
expensive, so wastage of tape had to be kept to a minimum for cost
reasons.

David Belcher