Southwark Bridge
Southwark Bridge is an arch bridge in London, for traffic linking the district of Southwark and the City across the River Thames. Besides when others are closed for temporary repairs, it has the least traffic of the Thames bridges in London.

Southwark Bridge is an arch bridge in London, for traffic linking the district of Southwark and the City across the River Thames. Besides when others are closed for temporary repairs, it has the least traffic of the Thames bridges in London.
Check the official site before travelling; hours and prices can change.
More bridges

Tower Bridge
The bridge people mean when they say London Bridge. Walk the high-level walkway for the glass floor.

Millennium Bridge
Foot-only suspension bridge from St Paul's to Tate Modern — the only crossing aligned on St Paul's dome.

Hammersmith Bridge
Currently pedestrian-only, Victorian wrought-iron beauty — best photographed at golden hour.
Source: wiki-list