In message , Bored Of The
Rings writes

Whatever happened to the extension south of E&C?

The 1949 plan shown on the map was abandoned because of cost (before the
war a similar plan had been curtailed to just a 515-foot siding beyond
Elephant).

and where was it gonna be extended to?

In that particular incarnation, Camberwell (Green). For more detail, see
the History section of:

http://www.davros.org/rail/culg/bakerloo.html

--
Paul Terry