Silk ties and handkerchiefs are forecast to rise in price after the cost of silk jumped to its highest level in at least fifteen years as rapid industrialisation in China, the world’s largest supplier, robs the sector of valuable farm land.

The price of silk cocoons, the raw material for the fabric used in expensive items of clothing, has doubled since the start of 2009 to 92,700Rmb ($13,577) a tonne in mid-April, according to the China Cocoon and Silk Exchange.

European merchants and weavers said the price of raw silk, the variety traded internationally, had followed a similar trend. “It is rising every day, every week,” said Christian Morel Journel, a silk merchant in Lyon, France.

The urbanisation of the key silk-growing region around Shanghai has reduced the land available for mulberry trees, whose leaves are the only thing silk worms eat.

“It’s as if you had a very large city in Champagne on the soil of the famous wine,” Mr Morel Journel bemoaned.

Chinese output fell 15 per cent to 84,000 tonnes last year, according to the International Sericultural Commission, and a drought that began in late 2009 has further reduced production. China accounts for 70 per cent of global silk production.

The rally coincides with a surge in the cost of other natural fibres: coarse wool, used for carpets, has soared to the highest level since 1980, while cotton is near a 14-year high.

Silk accounts for a small part of the final price of fine clothing. But David Tooth, chairman of Vanners, a 270-year-old silk weaver in Suffolk, England, which supplies brands such as Burberry and Ralph Lauren, expects retail prices to rise 10-20 per cent in the near term.

Demand of silk has sagged in modern times with the arrival of artificial fibres, which are cheaper and easier to clean.

The drop in supply has coincided with an increase in demand that has squeezed the market.