Unseasonably warm April weather could threaten the Bordeaux 2011 crop, winemakers have warned.

Warm sunshine across western Europe in the last week has produced temperatures in excess of 30 degrees C in Bordeaux, Decanter reports.

However, growers are worried that the fine weather may have brought the vines on too early, and now the delicate new buds are vulnerable to April frosts.

Pichon Lalande oenologist Thomas Do Chi Nam told the publication: "Yes, we are worried. A hard frost can kill buds when they are advanced."

He went on to explain that after a hard frost on April 21st 1991, between 15 and 20 per cent of the entire Bordeaux grape crop was lost.

Bordeaux's 2010 harvest was saved by a cool August, according to leading negociant Bill Blatch.

He told wine critic Jancis Robinson's Purple Pages website last month that after near-total drought in July, the cooler weather in the following month helped to preserve the acidity of the grapes.