A possibly 500-year-old Chinese vase fetched 810,000 pounds ($999,198) at a Birmingham auction house – 450 times its estimated selling price, as bidders gambled on it being an original and not a mere modern copy.

The intricately-painted porcelain wucai fish vase was valued by auctioneers Fellowsat 1,800 pounds ($2,220) after examinations suggested the decoration at the collar lacked the sophistication of original pieces.

However, the vase went on to smash all previous records at the Birmingham auctioneers on Monday morning after a bidding war broke out between two would-be buyers, pushing the price through the roof.

There is still debate over the vase's authenticity but, if proven to be an original, it could be worth millions.

The owner of the vase was described by Fellows as a Chinese client, based in mainland Europe, who wished to remain anonymous. The buyer was also from China.

In 2013, a wucai fish vase from the Jiajing period within the Ming Dynasty (1368-1644) fetched HK$25,880,000 ($3.33 million) at Sotheby's in Hong Kong.

The original modest valuation price at the Birmingham auction was in response to expert opinions that the vase may have beena 20th Century copy of a vase made during the reign of Emperor Jiajing, who ruled from 1521 to 1567.

Some collectors flew in from overseas while others took part by phone and through online bids.

Mark Huddleston, Fellows' senior specialist, said the auction house was delighted with the sale.

"A number of bidders were actually in the saleroom and had viewed it in person," he said. "One bidder even flew in from Japan. However, after initially strong bidding, he dropped out well before the half-million mark. Two buyers in the room battled each other strongly before, at around the 600,000 pound mark, the final telephone left standing sparked into life.

"Finally, at 800,000 pounds, the final bidder in the room admitted defeat."

Huddleston said, the telephone bidder, via his translator, secured the lot and a round of applause for the auctioneer and managing director, Stephen Whittaker.

"Whilst we dealt with a number of condition enquiries before the sale, little could have prepared us for the result," Huddleston said. "Bidding began at 1,000 pounds and, with a handful of telephone bidders plus the usual hundreds online, predicting the final price became impossible."

He said initial research showed there had been a number of historic precedents to the lot, "which were sold in the tens and hundreds of thousands".