Neil Spellings wrote to uk.transport.london on Wed, 5 Jan 2005:

The daily cost from a Zone 4 station for a variety of ticket types is as
follows :

Oyster-pre pay singles : 5UKP (2 x 2.50)
Monthly travelcard : 5.94UKP (116.80 * 12 / 236)
Annual travelcard : 5.16UKP (1216 / 236)

This doesnt include any days taken off sick (most people have a few per
annum) or any travel taken at weekends (which a travelcard would
cover), but overall, travelcards for Zone 4 tube travel are no longer the
cheapest option!

I wonder if TFL have spotted this anomaly?!

That would be true only if your travel was point-to-point on the Tube -
it doesn't work if you have to use the bus at either end, or change from
NR to the Tube.
--
"Mrs Redboots"
http://www.amsmyth.demon.co.uk/
Website updated 2 January 2005