Southwark deep level shelter entrance?

I don't believe there is any evidence on the surface of any of the entrances to the Southwark shelter. All bar one of the six entrances were backfilled after WW2, in the tunnels you can clearly see where they were, now secured with thick concrete plugs where the staircases formerly joined the tunnels, which confirms that the staircases and street entrances no longer exist.

The exception is the London Bridge Street entrance, where part of the staircase survives as an access to the shelter tunnels, its lower level connects to the northbound shelter tunnel, its upper level connects to a landing on the C&SLR spiral staircase at London Bridge station. Note this upper level is not its original upper level, and like the other entrances there is no trace at surface level.

Even the C&SLR spiral staircase has changed in recent years, with the former 1900 station building being (sadly) demolished in the couple of years.

At the time the shelter was given up, this staircase was the only access to the King William Street tunnels from within London Bridge station, however when the lifts were superseded by escalators in 1967 this made available a more convenient access via the disused lift shaft. There are also two means of access via Northern Line running tunnels in the London Bridge area (both securely locked!).

Another point of interest, there is no access from the Northern Line running tunnels into the shelter tunnels at the Borough end, as both tunnels are blocked by thick watertight concrete walls installed in 1938 at the time of the Munich Crisis. The southbound tunnel at this point was used during WW2 as a strongroom for important documents belonging to Southwark Borough Council.

Unfortunately none of these areas are accessible to the general public, and because of their generally hazardous nature are not suitable for visits.

Check out "London's disused Underground Stations" by J.E. Connor(Capital Transport) for photos of the 'before & after' conversion