Fourteen months late and more than £1.5bn over budget, the first stretch of the Jubilee Line Extension finally opened last Friday.

The opening of the £3.4bn project’s first phase, linking Stratford in east London and North Greenwich, guarantees public access to the Millennium Dome, the government’s car-free millennium showpiece, via London Underground.

However, doubts persist over whether the crucial central London link between Green Park and North Greenwich will be completed in time for the millennium celebrations.

London Underground chief executive Denis Tunnicliffe refused to give a precise date for the opening of the next section of the line, which will run from Waterloo to North Greenwich.

Tunnicliffe said: “We will not be giving a firm date for the rest of the line. We’re sticking to our dates of late summer and autumn.” But a London Underground insider said: “So long as the Waterloo link is open in time, the job is done. It will take the bulk of people from the passenger interchanges at London Bridge and Waterloo.”