I go through liverpool street station everyday on my way to work, and
Ive noticed these things about 3 metres high, and 3 metres across, that
are totally round, and appear to have air vents at the top. They sit
outside the offices of UBS in the broadgate centre, on liverpool
street, and are built in the same design as the rest of broadgate.

Now, I know a bit about the history of broadgate, and that it used to
be a mainline station called broad street, and assumed that these might
be the old lift shafts for the broad street entrance to liverpool
street central line tube station, since they seem to be close to above
where the bridge runs over the west end of the eastbound platform.

But recently I noticed that apart from the two near the bus stops,
there is a third seperated from them some way to the west, with a door
in it, so I was wondering what this might be, as it doesnt make any
sense.

Secondly, the other thing ive noticed is that, since liverpool street
mainline station was extended south by about half its size (you can
tell by looking at the dirtyness of the roof, and there is a join in
the brickwork at the far end of the busstops) in 1992, the underground
station entrances would be completely outside the original station. But
looking at some old pictures of the station, there is an entrance road
to the station there, so how did you get to the tube?