Jorvik Viking Centre could be closed for up to a year after staff lost a day-long battle to protect it against the floods.

The world-famous ride through Viking York under Coppergate is under half a metre of water and management cannot begin to assess the damage until it is cleared.

The cost of putting it back into action is likely to run into millions of pounds.

All the historic artefacts were saved and have been taken to other buildings and the Jorvik Viking Festival in February will go ahead as scheduled.

Staff put in a 24-hour shift, working under emergency lighting to keep the water out. One of them, Tony Mercer, said: "We were able to hold it for ten to 12 hours, then suddenly it rose. It was gutting."

Sarah Maltby, director of attractions for York Archaeological Trust, couldn't say when Jorvik will reopen.

"We need to assess the damage once we pump the water out," she said. "It could be a few months, it could be many months, up to a year."

The floodwater is contaminated, so the entire exhibition may have to be removed and replaced. Last time the Trust did a complete renovation, in 2000, it cost £4.5 million pounds.

But this time, on top of the cost of a new exhibition, the Trust will have to replace electrics and other equipment.

The Trust is yet to decide whether the shop will open before the rest of the attraction.