I was at Brockley station the other day and a train went through "overhead" as it were. I couldn't help thinking how easy it would be to create an interchange station by building platforms on the Lewisham/Peckham route.

More ambitious - and seemingly far too ambitious even to cross the mind of Boris or TfL - but increasingly necessary is extending the Victoria Line from Walthamstow Central to Leytonstone Underground Station. The eastern end of the Central Line is a self-contained loop because trains can be reversed at Leytonstone. When the Central Line is closed because of works or someone jumping under a train at Mile End, the Central Line keeps operating between Epping, Hainault and Leytonstone. As the Victoria Line has been resignalled and can now run a more frequent service, extending the line two miles to Leytonstone would provide real relief for the severely over-crowded Central Line.