In message , Marratxi
writes

Why does a hotel need an exit tunnel and why is it so big ?

It was the main exit from the station as well as the hotel (it is part
of the roadway goes right past the famous booking hall).

I was about to write that, despite all this, I don't think this is your
tunnel (it is slightly too far west) when I saw your latest post. The
explanation that it is a vault under the parcels office ties up with the
plan of the station given in London's Termini.

--
Paul Terry