TfL has confirmed that it anticipates significant disruption to London Underground services on Tuesday evening and throughout Wednesday, as a result of a 24 hour strike, called by the RMT and TSSA unions.
As ever, South East London should remain relatively unscathed. They say:
We expect all other TfL services, including London Overground, DLR and Tramlink, to run as normal, but they may be busier than usual. In addition, extra Bus and River services will be in operation. Cycling or walking may also be practical options for many.