In message
-sept
ember.org, at 17:28:55 on Thu, 3 Mar 2016, Recliner
remarked:

You are still fixated upon the position of the Victoria Line. What I'm
interested in is why the passageway from the Victoria to Piccadilly
doesn't emerge at the western end of the latter's platforms. And later,
the same for the Jubilee.

As I said upthread, they were almost certainly trying to avoid congestion
at the western end of the platforms as you already get queues backing up
from the escalators on to the platforms, even without mixing in all the
people heading to and from the other lines. This way, even though it
increases the walking distance for those at the western end of the trains,
is safer. And it doesn't increase the walking distance for the pax at the
eastern end of the trains. If you're at the western end of the Piccadilly
line train, just take the escalator up, and then the Victoria line
escalator down.

That doesn't explain why this is the only station on the network where
the up-and-back-down escalator workaround is required, or they worry
about mixing new and transfer passengers.
--
Roland Perry