Stephen Lewis sneaks a look around the new high-rise Viking metropolis of Jorvik

'If people still call it a village after this," says Richard Kemp, "I will scream!" We are standing in the middle of the restored Viking thoroughfare of Coppergate. And Richard's right: anybody who could think this is a village is at least two planks short of a longboat.

The street is lined with imposing two-story buildings: and it's bedlam. All around us, tradesmen are hawking their wares - blacksmith, fishmonger, coin-striker, bone and antler-worker. People are bargaining, arguing, gossiping; dogs are bickering, chickens scratching in the dirt.

"All human life is here," says Richard, gesturing around. "The noise, the smells, the commotion: it really gives you the feeling of being in an important city."

The true size of Jorvik only becomes apparent, though, when I catch a glimpse between the gabled roofs northwards towards the Viking Minster.

"Can you see it?" says Richard, York Archaeological Trust's director of attractions, excitedly. "All those rooftops; the smoke of 10,000 hearths rising in the distance ..."

For a moment, tantalisingly, I can. And then the spell is broken. Viking Jorvik, October 25, 975 AD, fades away: and instead we're standing on a half-completed set in a warehouse just outside York. Underfoot are wooden struts covered in chicken-wire: to each side the half-completed frames of what will be reconstructed Viking town houses.

For several months now, workmen have been building the 'new' Jorvik Viking Centre here. Come October 31, when the existing centre closes its doors for the last time, this entire set will be transferred lock, stock and barrel to the site of the Viking museum beneath Coppergate. The Viking City of Jorvik will be born.

It promises to be quite an experience. The Jorvik Viking Centre broke new ground when it opened on April 14 1984. But since then, museum technology has moved on: and so has archaeologists' understanding of the ancient Viking city.

'New' Jorvik will use state-of-the-art technology and the results of a further 16 years study of the Viking remains at Coppergate to recreate the Viking metropolis - one of the greatest European cities of its day. Richard himself admits visitors who have left the Viking Centre in the past thinking it was a reconstructed village had some excuse. Because of the layout, the main thoroughfare of Coppergate is almost entirely lost.

The celebrated 'time cars' instead pass down a narrow back alley between wattle-and-daub homes, far from the hustle and bustle of the city centre.

Because of the need to make room for the time cars, the homes don't even have dividing fences: leaving the impression the Vikings had no concept of private property. "It's a bit like a hippie commune down there," Richard conceded.

In New Jorvik, all that will be changed. The reconstruction will have doubled in size, and many of the present wattle-and-daub homes will be replaced with imposing two-storey timber structures - 'High Rise Jorvik', Richard calls it.

To heighten the sense of reality, the reconstruction is to be rotated through 180 degrees: so that the reconstructed Viking Coppergate will be directly beneath today's Coppergate.

For the last 16 years, visitors have been going to a 'backwards' Jorvik where everything is the wrong way round.

In the new Jorvik, every reconstructed street and home will be built precisely on the spot where archaeologists know it actually existed.

"Jorvik is not a foreign place: it is York," says Richard. "The idea is for it to be a continuation of Coppergate: the very street the Vikings laid out in 910AD.

"We're building a Viking city, and we're building it in the actual, archaeological holes that were dug."

Entry to this Viking metropolis will be through a new, revamped lobby. Visitors will be whisked back to 975 AD in a state-of-the-art time machine.

This is what the experience will probably be like: "Welcome to Time Warp Transportation," a sign proclaims as the doors of the time machine close: "Target Date 975."

A viewscreen fills with a modern-day York street scene. The machine starts to vibrate as its journey back through time begins, the dateometer clicking backwards faster and faster. As it does so, the scene of Coppergate on the screen itself morphs backwards through time.

Back in 975 AD we step out into Jorvik. We're on the banks of the River Ouse, looking through trees up towards Coppergate. A time capsule suspended from the ceiling approaches and we're off. It lifts us up the sloping bank of the river towards Coppergate.

As we go it pans left, to give us a view of an imposing two-storey timber antler-worker's home, then right to a painted panoramic view of the Jorvik roofscape.

At the top of the first street we reach an older, lower, wattle-and-daub house. It's a blacksmith's: from inside comes a blast of heat and the 'clank! clank!' of the smith's anvil.

We're aware of another noise, too: the distant sound of a great thoroughfare somewhere just off beyond the next row of houses. Coppergate: although we can't see it yet. We turn left down a narrow street instead, then left again, back towards the river. A new timber house is under construction: we watch the builders at work. Back at the river, we do a sharp about turn and move steeply back up the bank to a long building like a banqueting hall.

A channel is cut into the riverbank leading into the building's cellar. Our time capsule takes us through. It's full of barrels just unloaded from the boats moored outside. There's a trapdoor in the ceiling: the time capsule takes us up through it, and we're in the family's living quarters: the whole family gathered around the hearth.

The capsule passes through, and out the front door: and suddenly the bedlam that is busy Coppergate hits us: street hawkers, noise, smells, the distant view of the Viking Minster.

The capsule takes us along Coppergate, and at the end we turn right and down, back towards the river.

We pass through another building - and as we do so, something odd happens. One moment, we are in 975 AD: then, gradually, it fades out and we're back in the present, blinking and bewildered, in the actual archaeological remains of the reconstructed Viking building we've just been moving through.

Richard says it is one of the highlights of the tour: a chance to see the actual archaeological remains within the reconstruction itself.

"This is the real McCoy," he says, gesturing about him on the bare set. "The real 10th century timbers laid down by real Vikings.

"This is not Disney. The reconstruction is just a vehicle to make people focus on the real thing. I want people to come out thinking: 'Goodness me! So that's how they know!'"

The tour's not quite over. There's a 'recovery room': and then an objects gallery which promises a few hi-tech tricks of its own.

Finally, visitors emerge blinking into the shop and then the street.

And hopefully, says Richard, they will be looking at it with new eyes.

The Viking City of Jorvik is scheduled to open on April 14 next year, 17 years to the day after the original Jorvik Viking Centre opened.