Giant truffle to sell at celebrity auction

The biggest white truffle found in half a century, sniffed out by an Italian mongrel dog named Rocco, is to go under the hammer at a star-studded charity auction in London.

Madonna and her husband Guy Ritchie, whose son is also called Rocco, are expected to join the likes of Kate Moss, Elizabeth Hurley, Jamie Oliver and Cate Blanchett for the Sotheby's sale tomorrow.

Organisers hope the 1.5 kg (3.3 lb) truffle will fetch in excess of £100,000 - which will render it ounce by ounce more expensive than gold.

The Tuscan truffle hunter Christiano Savini told how his dog, specially trained to locate the delicacy underground, started digging furiously towards the source of "the incredible smell".

"I had to tie Rocco up, he was so excited," he said. "My family has been truffle hunting for the last four generations and the emotion I felt when I found this beauty was so intense."

It took more than an hour for Mr Savini and his father Luciano to carefully brush the soil from the giant fungus buried 75 cm (2.5 ft) deep near an oak tree in the Tuscan countryside.

Ten years ago the pair found a half-kilo white truffle by the same tree in a secret spot near Pisa.

Although it beats the Guinness World Record of a 1.3 kg (2.86 lb) white truffle found in Croatia in 1999, the Savinis' latest find is believed to be second in size to a 2.5-kg truffle presented to former American President Dwight Eisenhower in 1954.

Rarer than the black variety, the white truffle or Tuber magnatum grows around Alba in northern Italy and on the Istria peninsula of Croatia. Following a dry summer, crops were down and prices up.

"The truffle we found benefited from the 15 days of rain we have just had," Christiano Savini said.

"As the news spread I had ridiculous offers for the truffle - someone offered me £70,000. I decided that the best thing to do was put it up for auction," he added.

Giselle Oberti, the auction organiser, expects more than 200 people to take part in the bidding, which will run simultaneously at three locations - Giorgio Locatelli's exclusive restaurant Refettorio near Blackfriars, the Palazzo Medici in Florence and The Grand Lisboa hotel in Macao.

The buyer will have less than a week to eat the knobbly fungus, which has to be consumed within 20 days of being unearthed. In 2004, a 700 g truffle sold for £28,000 at an auction reportedly attended by Roman Abramovich and Gwyneth Paltrow - only to get mouldy in the safe of a London restaurant.

The Savinis decided to donate the proceeds to an Italian organization that helps sufferers of genetic diseases, a group that helps street children in London and Catholic charities in Macau.

"This truffle was a gift from God," Christiano Savini explained.

And as for Rocco? He, at least, will get a new kennel.