It looks like from December 2009 the Circle line on London Underground will be extended to Hammersmith. Normally the Circle line consists of two services, eastbound and westbound and these keep going round and round hence the name. The problem is that there are other tube lines running over the same tracks, the Hammersmith and City, and Metropolitan along the top, and the District along the bottom, so any problems or delays on those lines usually translate into delays on the circle.

Soon though the trains will have a terminus in Hammersmith and will go from there round the loop clockwise to Edgware Road, then will do another circuit anti-clockwise back to Hammersmith. This has been jokingly described as a teacup.

The theory is that because trains have a fixed starting and end point they will be able to recover quickly in case of problems, although for travellers a lot of the convenience of being able to board at Notting Hill Gate and travel directly round to Kings Cross or Euston will be gone, and these travellers from the western side will have to change at Edgware Road to carry onwards along the top section.