Health experts are examining the Marriott Castle Harbour Hotel's water tank as the possible cause of a mystery epidemic that has claimed more than 200 victims.

The new line of inquiry contradicts evidence given by health chiefs yesterday that the virus was introduced by an outside group who visited the hotel two weeks ago.

And in a new twist hotel guests revealed that part of one of the hotel's restaurants had to be sealed off on Friday after filthy, foul smelling water leaked from a blocked sewage pipe.

Hotel bosses confirmed that an outside safety consultant has been brought in to examine the tank, as well as to study other sanitation procedures.

And the Government's Chief Environmental Health Officer, also confirmed that the tank would be emptied and cleaned as a precautionary measure.

The new development could leave Government health bosses red faced. They inspected the sight last Friday and claimed that the virus was not spread through food or water. Within 24 hours more than 100 people at the hotel became violently ill.

Yesterday The Royal Gazette was flooded with calls from hotel visitors who claimed they became violently ill after drinking water or ice at the hotel.

But Chief Medical Officer Dr. John Cann said he believed the virus was spread through poor human hygiene and sneezing.

It is now understood that no new cases have been diagnosed at the hotel since it disconnected its water supply on Monday.

And although Dr. Cann dismissed the possibility that the hotel's water tank was the culprit he has since said that all those hit by the bug had drank water from the hotel.

In the past two days Dr. Cann has repeatedly stuck to his original diagnosis.

Last night a spokesman from the Department of Health said: "Investigations to date confirm an epidemic viral gastro-enteritis, probably caused by a virus known as the Norwalk agent.'' "It is likely that the viral agent first spread among a visiting group and then spread to some hotel workers and other guests at the hotel.'' Mr. Cann's remarks have come under continual attack from both hotel guests and medical experts.

One retired doctor who caught the bug told The Royal Gazette that Dr. Cann should "go back to school'' because his theory was totally incorrect.

"I was at the hotel on Saturday night and both myself and my wife became ill,'' the doctor, who does not wish to be named, said.

"But what we had was definitely a serious toxic poisoning, passed on through food or water. It's ingested rather than a virus which you can pick up from other people. I think Dr. Cann should go back to school.'' Another retired doctor described Dr. Cann's explanation as "puzzling''.

"It certainly seems as though it's come from the water supply,'' he said.

"If it was a virus, why hasn't everyone else come down with it?'' Last night hotel bosses were not prepared to say whether they thought health experts had mistakenly given the hotel the all clear when they first inspected it last week. Resident manager Scott Hendrick said: "It's too early to talk about that sort of thing.

"At the moment our main concern is for the safety of our guests and the public of Bermuda. We are doing all we can to get to the bottom of this and expect some answers by the end of the week.''