On 14 Jan, 20:16, lonelytraveller
wrote:
On 14 Jan, 04:35, wrote:

There was an exit at the extreme rear end of the EB Central Line
plaform. You went up stairs then turned right into a corridor which
lead due north to reach the lifts lower landing. At top level these
lifts allowed access directly onto the concourse of Broad Street BR
station. All this was still there disused until the Broadgate Centre
was built in the mid-1980s.

Do you happen to know where the spiral staircase was, and what
happened to it?

The is a "lift shaft" type area located between the platforms towards
the middle. It's now a pump room (the pump was prone to fail not so
long ago, causing flooding on the platform). As others have said, the
escalator shaft towards Broad Street was located at the west end of
the platforms, up some stairs and along a passage, coming out where
the bus station now is.