Graeme Wall wrote:

It is an urban myth that Doctor Who ever went out live. It was simply
recorded "as live" for the first few years due to the difficulties in
videotape editing.

It certainly went out live in the very early years, most BBC programmes
did.
Z-Cars was transmitted live well into the 1970s. By then it had become a
fetish for that programme and there were long and loud lamentations when
they
went recorded. The reason being to do with studio scheduling rather than
editing.

I disagree - a lot of research has been done that shows that Doctor Who was
recorded in advance from the outset.

Z-Cars seemed to still do live episodes in 1965 but this was even then
regarded as anachronistic.