Transport for London has a new leaflet out explaining the forthcoming changes to the Circle Line (from 13 December). They are still going to call it the Circle Line, though it will be in the shape of a teacup, not a circle.
I hadn't previously quite understood that the Hammersmith and City line will still exist as a separate entity. When TfL says there will now be a train every 5 minutes between Paddington and Hammersmith, I take it to mean a Teacup train every 10 minutes and a H & C train every 10 minutes. This is certainly a remarkable increase in overall frequency on that section, which used to be notoriously unreliable and sporadic, at least it was in the early 1980s when I was living in Shepherds Bush.
Chaos can, I think, be expected on 13 December at Edgware Road. The leaflet makes a lot of the fact that, although some passengers will have to change trains there who up to now have had a through service, it will be an easy cross-platform interchange. In fact, this is not always the case. If you are going from, say, Great Portland Street to High Street Kensington (a direct journey by Circle train at present), your Teacup or H & C train will arrive at platform 4. The next High Street train might be across the platform at platform 3 (for Wimbledon) but it might equally be over the footbridge at platform 2 (an anti-clockwise Teacup train).
This is a good example of the iron rule that every transport improvement silver lining has a cloud for certain users.