Londoners have seen nothing like it. Vast, subterranean, airy cathedrals of commuting replace the draughty, crumbling labyrinth of tunnels and ticketing halls that stain the memory of the travelling public. This is the first glimpse of the 10-mile, pounds 2.7bn Jubilee extension (JLE), due to open in autumn, which will squirt millions of passengers south and east of the present Underground network.

Europe's largest construction project, the line is a site for superlatives: the 116 escalators for the stations compare with a total of 243 on the entire existing Underground system. Westminster station, the crux of the project, will link the congested District and Circle lines and at 38m is the deepest building site in London. More astonishingly, Britain's tallest skyscraper - the 50-storey Canary Wharf Tower - is still some 50m short of the length of its JLE station.

The line's inspiration lies in the Far East. Its chief architect is Roland Paoletti, whose Hong Kong Metro revolutionised underground-station design. He and his architects, including the radical chic clique of Sir Norman Foster, William Alsop and Michael Hopkins and young guns such as Chris Wilkinson, will produce an underground landscape that will be unrivalled by any other metro system around the globe.

Conventional wisdom is that before the Second World War London enjoyed the best-designed, most closely integrated and most efficient urban transport system in the world. The Underground of the Thirties was characterised by its scale and efficiency and also by the architecture of stations built along its extensions. Designed for the most part by Charles Holden, its apogee was Gants Hill. However, as Tube investment was shredded by subsequent governments, it looked as if the standards set by Holden would never be repeated. However, Mr Paoletti says he is not the inheritor of Holden's legacy. "Even with Holden, the thing was a labyrinth, an underground rabbit warren. Later on, it became an ad hoc thing. Those designers were like plumbers - you know, putting a tunnel here, a platform there. There was no invention."

The new architects, says Mr Paoletti, were given the barest of guidelines. "I knew these people were good. You do not need to tell them what you want." The only golden rule was to create stations which have a "logic to their layout ... this means that travellers instinctively know where to find the platforms and the exits."

Passengers will see daylight filtering down to platform level - a design requirement. Each platform will be faced by sliding glass screens to prevent passengers falling under trains. These will open only when the train doors open. This also means the rush of air that whips through most Tube stations will be absent on the Jubilee extension.

It runs from Westminster south of the Thames through Southwark and Bermondsey before crossing under the Isle of Dogs at Canary Wharf to the Millennium site at North Greenwich before swinging north through east London to Stratford. North Greenwich, designed by Alsop, Lyall & Stormer, is, at 400m long, the biggest underground station in Europe. Originally conceived as a park- and-ride scheme for drivers from Kent who wished to avoid the congested Blackwall tunnel, its exit now lies "15 yards from the Millennium Dome".There is room for more lines to be added. "It can cope with 17,500 people an hour," said Mark Glanville, the station engineer. "But only about 12,000 people every 60 minutes will use it to begin with. You need the extra space because the designers could add another set of tracks going to Woolwich."

With blue glass illuminated by low-level lighting and a walkway suspended by steel bars, North Greenwich - likely to be renamed "Millennium", as it will service the Millennium Dome - is a far cry from the clutch of tunnels and platforms covered in psychedelic mosaics that litter the current network. Sir Norman's pounds 100m Canary Wharf station is another wonder- of-the-world-in-waiting. The 300m station, which will be reached by glass domes - whose panes are from a factory that supplies Ferrari with windscreens - will feature 20 escalators.

"By 2010 Canary Wharf will be the second-busiest station in London," said Dennis Drake, the station's senior engineer. "We will be looking at handling 35,000 people in the morning peak hour."

The first new stations since the Victoria line in the late Sixties will link parts of London previously isolated from the capital's transport system. "At West Ham at the moment there are probably in the peak four trains an hour. When the Jubilee line is fully operational there will be 36," said Kevin Otto, train manager for the JLE.

Tracts of London - especially in the south - have been untouched by underground trains because of the geology. Unlike north London, which is built on clay, the material underneath is mostly gravel and sand, which is difficult and costly to drill through.

It has already been noticed that the prospect of a Tube journey into the West End in 20 minutes has sent property prices spiralling in Greenwich, Canning Town and Bermondsey. The line has not been without its difficult moments. Many know it as the line designed to bale out Canary Wharf, the massive and controversial Docklands development built by Olympia & York at ruinous cost and without transport infrastructure. Now the developers will pay a pounds 400m contribution over 25 years towards the cost of building the Jubilee line, which the Reichmann brothers - who conceived the development - had promised. However, a deal was struck after the Major administration said it would move thousands of civil servants to offices in Canary Wharf.

In addition to costing pounds 800m more than the original pounds 1.9bn budget, the Jubilee extension will also open late - originally scheduled for a March 1998 start, the first of the 59 new trains will trundle along the tracks in September. And the signalling system - which would allow trains to run without drivers - is not working properly, so the line will only see 17 trains an hour running. And engineering problems mean Westminster station will open late - forcing travellers to change trains at Waterloo. Despite all this, the new line will change London as we know it. The promise of a trip into town in 10 minutes has seen firms flock to Canary Wharf. Citibank is moving into a 11-storey tower block with an entrance into the JLE station as part of the package.

A riverside leisure complex - featuring apartments, health club and a five-star hotel, is being built.

With stations linking Stratford, West Ham and Canning Town to the centre of town, it is not so much the East coming to London but capital going to the East.