In message , Paul Terry
writes

Could the arches have supported the horse ramp to the original London &
Greenwich terminus (bearing in mind that the ground level in the area
has risen progressively over the years?

Following-up my own post, but the following clip from an 1865 map shows
the remnants of the ramp, passing under the Charing Cross extension - it
looks like an unnamed road that continues along the original alignment
of the London & Greenwich Railway, ending in Wellington Street just
below London Bridge itself.

http://archivemaps.com/mapco/whit1865/whit44.htm

The map also shows the original buildings of St Thomas's Hospital still
standing - the Charing Cross extension crosses only a tiny part of the
site that the SER was forced to purchase in its entirety - Station
Approach was built on this site.
--
Paul Terry