So suggests this report, based on a meeting of the London Assembly's
Transport Committee - Kent County Council being the active objector to
the TfL rail takeover plan in revenge:

http://www.bbc.co.uk/news/uk-england-london-33066006

Hopefully it'll be an idea that'll surface again in the future - so long
as TfL does a good job on their new West Anglia metro routes.