Peter Masson wrote:
"Mizter T" wrote

LNER - this is in connection with the abandoned Northern Heights
extension of the Northern line over LNER lines. I must admit I can't
remember whether any LNER trains would have actually served East
Finchley should the project have been completed.

Between July and September 1939 East Finchley was served by Northern
Line trains to High Barnet and LNER steam trains to Edgware. From
then until March 1941 steam trains continued to run to East Finchley,
but the service to Edgware was withdrawn to facilitate doubling and
electrification. From May 1941 Northern Line trains began to run to
Mill Hill East, but further work on the Northern Heights scheme was
suspended for the duration, and never resumed.

AIUI the eventual intention was for the whole passenger service to be
part of the Northern Line, with services from Morden via Charing
Cross and Bank to Edgware via Golders Green and to High Barnet, and
from Moorgate via Finsbury Park to Edgware via Mill Hill East and to
Alexandra Palace (the original branch line station, not the current
one which used to be named Wood Green). The LNER would have continued
to operate freight services to High Barnet and Edgware (as indeed BR
did until the 1960s).

So if there was no long term intention for LNER to serve the station, I'm
surprised that the 1930s rebuild included an LNER logo built into the
structure.