JUST a few feet in front of you, a middle-aged man squats above a stinking cess pit, his face grimacing as he groans with the strain, with only a wicker fence to half-obscure the view. Not something most people would pay to see but, in this case, it's all part of the attraction.

Indeed, visitors to the refurbished Jorvik Viking Centre in York could be forgiven for thinking there was a bit of an obsession about bodily functions. As well as the cess pit scene, there is also a display board on the subject, complete with a specimen of human waste. And some moss.

But, far from being an unhealthy preoccupation, it is all part of the centre's determination to make authenticity its watchword, following a complete overhaul.

"We know from our research that everywhere you looked there was poo, poo, poo," says director Richard Kemp. "Not just human stuff, but dogs' and pigs' as well. It was everywhere.

"We are going to have an example of poo and maybe moss as well, which was what they used as toilet paper, alongside strips of cloth. When we were excavating the site, we kept finding cloth at the bottom of cess pits and we thought it was organic debris.

"It was only when we started picking bits out we realised they were corners of cloth they used as toilet paper. They obviously used to tear their old clothes into strips."

And it's not just the excreta which gives a human touch to the exhibitions. Also on display are ribs of beef, with knife marks made by a Viking butcher.

"We wanted to make it human, and also show the evidence," says Mr Kemp. "Everything we say about what went on at Jorvik we can support with evidence."

When the centre first opened in 1984, one of its key innovations was recreating some of the smells of life in the Viking age. And, alongside the animatronics making some of the figures move, including the straining man, smell is an important part of the experience of the new Jorvik.

Visitors passing through the Viking city in the new timecars - this time suspended from an overhead monorail instead of running along the ground - get a distinctive and unpleasant whiff of sawn bone, oak from the wood-turner's house, the cess pit, straw on the hearth and soil from the archaeological dig, as well as a blast of heat from the blacksmith's forge.

But, strong though some of these smells will be, modern sensibilities are not quite up to the fully authentic experience. "We cannot ever make this place smell exactly like it did in the Viking period because we would not get any visitors. The whole place would reek," says Mr Kemp.

"Everybody would smell of wood-smoke anyway, all their clothes would be saturated. They would be used to it and wouldn't notice it but to us it would be overpowering, so all we can do is suggest and hint what it would have been like."

The original Jorvik exhibition was set in 948AD, but the £5m redevelopment has seen it updated to 975AD, when the settlement underwent a rapid expansion, with its population swelling to 10,000, making it the largest and most important city in the North of England.

And the display has been expanded to emphasise this, with more houses, more noise and a cityscape along the walls to try and give the impression of a bustling city.

"I did love the old Jorvik, it was the most wonderful exposition of archaeology you could find anywhere, and people loved it, but it didn't work on every level," says Mr Kemp. "We found that 84 per cent of our visitors thought they had been round a village, and the rest thought it was a farm. They didn't realise it was a city. We have increased the area for reconstructions by 160 per cent and if we can demonstrate that you are visiting a city then it will feel different.

"This was a big place, it was the North's premier city. It had an archbishop, it had a mint, it was the centre of judicial functions. It was the Hong Kong or the Tokyo of its day."

Jorvik was based on excavations at the Coppergate site carried out between 1976 and 1981, but subsequent research has shed more light on the finds and their importance as part of the development of the Viking community.

And many of the results can be seen in the completely remodelled artefacts gallery, which also benefits from an innovative approach to display items recovered from the site.

Everyday objects, from sewing needles to door hinges, are seemingly arranged randomly inside glass cabinets. But a trick of lights and mirrors then sees them take up positions in the hands of Viking craftsmen or conveniently placed around a workshop.

This aims to provide a setting for the artefacts, showing how they would be used and doing away with the need for lengthy explanatory boards, off-putting to many museum visitors. And it also attempts to tackle one of Mr Kemp's biggest bugbears about the centre's first incarnation.

"What used to drive me berserk about the old exhibition was that people used to go straight past the artefact gallery. We want them to stop and look. Anybody can make scenic plaster, all we're using is Disney-type techniques, but I believe this method of showing artefacts is unique. We're trying to help people work out what the objects were for without having to resort to labels, although there will be some labels if they can't."

The lights and mirrors trick is also used as evidence to support the archaeologists' claims about the way the Vikings lived in the 10th Century, what they wore, what they ate, what games they played - as well as their toilet habits.

"The significance of many of these finds has only come to light as a result of the last 20 years of research, and our perspective has altered a bit as well," says Mr Kemp. "This is about what we found on the site and what we know about Jorvik. The objects are not particularly exceptional, they are everyday objects. You can go to all sorts of other museums to see treasure. We want to show evidence that supports our archaeological interpretation - bits of cut-off animal bone speak volumes about what was going on in the street.

"What this does is show you can trust everything you see when you come through this place. We're saying to people they can take whatever they want from this. If they don't read a single word they will still understand the big message about the relationship between archaeology and reconstruction. I hope we're giving people an accessible display. I can't stand it when people leave the centre, not interested in artefacts and getting the wrong end of the stick. That is what has driven me."

* Jorvik opens from 9am to 5.30pm and admission is £6.95 for adults, £4.95 for children and £5.95 for concessions. Timed tickets can be booked in advance on (01904) 543403.