http://www.london.gov.uk/view_press_...eleaseid=20938

Hallelujah! Phase 2b of the East London Line Extension, which will
link the existing line south of Surrey Quays to Clapham Junction via
the 'South London Line' railway has finally been given the full go-
ahead after an eon of prevarication, in part the result of squabbling
between the DfT and TfL/ the Mayor of London over funding. Whilst the
latest negotiations are almost certain to have had a political angle,
what with the different political hues of Boris and the government,
this is a saga that has been going on for a lot longer than the
current Mayor is likely to have known what ELLX phase 2b actually
meant (which should perhaps be borne in mind when it comes to handing
out the credit - but fair play to him in so far as he recognised the
importance of the project and pushed ahead with it).

The East London Line link to Clapham Jn will provide an abundance of
orbital journey possibilities.

Phase 2b is shown on this map in light blue (PDF):
http://www.tfl.gov.uk/assets/downloa..._route_map.pdf