On 28 Sep, 08:28, Roland Perry wrote:
I have no idea what that is (and therefore how long that is), sorry. For
example, are we talking more or less than the distance between the
platform faces?
The visible portion is slightly shorter than the distance between the
platform faces of the northern line.

At the end, does it disappear to the left, or the right?
To the right (the north)

However, we now seem to have cleared up the confusion between "facing
the opposite way", and "turning round" (which at first sight are the
same activity)... and therefore the new passage would seem to head east
and not west. That is much more consistent with being a link to the
other new lifts which are on the reconstructed Pentonville Road passage,
and (if they also have a "secret doorway") would link all three of the
new deep lifts together for emergency purposes.
No, it faces west. All phrases such as "facing the opposite way" and
"turning round" should be interpreted so that you face west at the
end. Go there yourself, and you'll see. The passage faces west. Its a
physical thing, and no amount of argument about semantics will ever
change the way it actually physically faces.