Both the Mayor and Transport for London have expressed dismay at the probable overrunning of maintenance work on the Jubilee Line. Tube Lines, the private company responsible for the upgrade programme, and contractor Bechtel reckon they can still conclude work by their deadline of December, but TfL think this unlikely. London Underground's annual PPP report, published today, spells out 'grave doubts' about the timetable. Boris described the situation as 'unacceptable', saying he is 'hugely frustrated' at progress. The Jubilee Line has been closed almost every weekend since February 2007, screwing up the travel plans of anyone wanting to reach the O2, or north-western areas that have no alternative line. London Underground have now called for an independent review of the works programme and threatened Tube Lines with large fines if the upgrades stall further. The PPP report does harbour some positive news, however. Tube Lines' work on the Northern Line (which we witnessed first hand) has led to a measurable improvement in service, and upgrades to other routes (notably the Victoria Line) have made good progress. Image by Andy Wilkes.