Under tough new American management, an integral stretch of the route was due to open in "late summer" and not a moment later. Yesterday, however, the season ended.
Under the Oxford English Dictionary's definition, the one favoured by management, summer evaporated on 23 September with the autumnal equinox.
And although London Underground opened part of the new east London section last Friday, as far west as Bermondsey, it was not able to extend it further west to take in London Bridge and Waterloo.
London Underground was still hoping to start running services to Waterloo today, but the trains would pass straight through London Bridge and Southwark, because the stations are not ready. It hopes to open London Bridge in "a week or two"; but a second 24-hour unofficial strike next Wednesday by electricians at the JLE will not help it meet deadlines.
John Prescott, the Deputy Prime Minister, has registered an interest in a ceremonial opening of the extant new stretch of track. He might finda limited audience, though - London Underground gave about an hour's notice last time it opened part of the line.
Tube managers would not commit themselves yesterday to predicting that Bermondsey- Waterloo services would start today, but they did concede that summer was over. Unless, that is, they decide to use the definition of summer ventured by a JLE spokeswoman re-cently, as extending until 31 October, the end of British Summer Time.
The final part to be opened, from Waterloo to Charing Cross, will be unveiled in "late autumn". No one at London Underground was able to say how autumn might be squeezed between 31 October and winter.