TOKI’S grandfather isn’t best pleased when we stumble across him in the privy in his back yard. Judging from the noises he’s making as he squats behind the wickerwork privy fence, he has eaten something that didn’t agree with him.

“Hei! Hvat gerir pu?” he shouts crossly in Old Norse as we pass. No, he’s not swearing at us, honest, says Sarah Maltby, Jorvik’s director of attractions. Our ‘guide’ – a recorded commentary playing from the headrest of the time car we are travelling in – offers a suspiciously cleaned-up translation. “Hey, what are you doing? I am… occupied.”

The old Viking doesn’t leave it there. Seeing us still lingering, he delivers another verbal volley. “Far a braut! Ok angra annan mann – Go away and annoy somebody else!”

Toki’s grandad is one of seven new animatronic Vikings brought in to freshen up Jorvik as part of a £1 million refurbishment.

There is Sigurd the antler worker, who greets us genially and explains about the bone comb he is making; Unni the wood turner, who is busy making a wooden spinning top for the children from next door; a couple in Coppergate Market arguing about what to have for dinner; and two Viking labourers who are supposed to be building a new, timber framed house. Instead, like workmen down the ages, they are enjoying a snack break.

“Hei, menn, hvi vinnid per eigi!” comes a shrill from behind us. It is a woman leaning on another wicker fence, scolding the two men for being lazy. “Pat hus er at timbre – That house needs to get built,” she says.

The new-look Jorvik is much more noisy than the old version. Everywhere, people are shouting, squabbling and gossiping.

Many of the animatronic Vikings that populate the underground city are the same as before – such as the two children playing hnefatafl, or Viking chess, and the market traders in Coppergate itself. But the lighting is much better, and the whole city has been opened up, so that as you travel through it you can look back across the wicker fences – they are known as hurdles, Sarah explains – that separate the back yard of one Viking house from the next. That, combined with the new artwork on the walls which shows the city receding into the distance, gives you a proper sense of the size of the city.

There is also an entirely new building, the amber worker’s house, that wasn’t there before. And children will be delighted to see a rat gnawing on bloody bones near the butcher’s house.

The fact that so many of the animatronic Vikings now talk adds to the immediacy. But it is Toki’s grandfather seated on his toilet who is likely to be the star attraction. He is the last character you pass as you leave the city. He grunts and strains enthusiastically, before turning his anger on you. Children will love the expressions on his face.

This museum is most famous for the time car journey through the recreated Viking city, built on the site of the original Viking city excavated underneath Coppergate.

But the most striking difference about the revamped Jorvik is the entirely new gallery that has been created before the ride. The old time car that used to sweep you back to the tenth century has gone. Instead, the original archaeological dig has been recreated. A glass floor lit from beneath covers most of the gallery, with a wooden walkway around.

Walk or crawl across the glass, and you can peer down at the outline of timber and wattle Viking buildings beneath you. They are recreations – but they are right on the site of the original dig, and look just as they might have done when archaeologists were sifting through the mud here back in the 1970s.

It is a stunning gallery. Walk across the floor and you automatically trigger audio presentations beamed from the ceiling, which tell you about the dig. And there are four video recordings being played on the walls as you go around, telling you about Viking Britain, and the lives of the Vikings themselves.

You can spend as long as you like here, before taking to the time cars, Sarah says. The aim, with this new opening gallery, was to create the wow factor. The designers of the new-look Jorvik have certainly achieved that.

• Tony Robinson officially opens the new Jorvik tomorrow. All tickets for the day have already been assigned to winners of the recent York Residents’ First competition. The centre will be fully open to the public from Saturday.

• Entry to Jorvik is £8.95 for adults, £4.50 for children. There are also family tickets available. A ticket entitles you to return as often as you want during the year. The time car ride lasts about 20 minutes. But, provided the queues are not too long, once you have taken the ride and visited the other galleries, you are now allowed to go straight back to the beginning and start again.