http://www.tfl.gov.uk/roadusers/cycling/11701.aspx

Sorry - finger brain-finger interface malfunction sent the above before
I had added "as you have probably seen shows only extra restrictions on
Overgound, but I found several errors in the roads section of
getaheadofthegames site so I'd email or phone TfL before attempting to
assert a right to travel"

--
Robin
reply to address is (meant to be) valid