I've just received an email from London Travelwatch with the following
information - something good from FCC, at last:

First Capital Connect has announced that, from January 2007, as part
of the introduction of zonal fares that all their stations in Zone 1
including Farringdon will be classed as London terminals when buying a
ticket. This means that Kings Cross will now be classed as a London
terminal when travelling from the south, and City Thameslink,
Blackfriars, London Bridge and Elephant and Castle will now be viewed
as London terminals when travelling from the north. The confusion the
current arrangement has caused has been a real passenger bugbear for
many years, and has turned up periodically in our complaints file, so
we are extremely pleased that FCC are rectifying the matter, meaning
many passengers will pay less for their journeys.

Al Holmes