It is the ultimate status symbol for wine buffs and commands astronomical prices, but Petrus risks losing its cachet after a French court rejected its plea to retain exclusive rights to the hallowed name.

After a seven-year legal battle, the Bordeaux appeals court has ruled that the makers of a cheap, blended wine that sells for less than £10 a bottle can continue to use the name ‘Petrus'.

The court quashed a petition by Château Petrus, which produces the original Petrus, to force the makers of the humbler Petrus Lambertini to drop the word ‘Petrus’ from their brand name on the grounds that it was misleading.

Petrus, known as the “Rolls-Royce” of clarets and favoured by oligarchs and City high-fliers, is produced in Pomerol, the smallest and arguably the most prestigious of Bordeaux’s wine-growing regions.

A magnum of its 2015 vintage costs more than £5,000, and the average price of a bottle of Petrus exceeds £1,800. Unlike many other “grands vins” of Bordeaux, which also produce cheaper “second wines”, Petrus makes only one high-quality vintage.

By contrast, Petrus Lambertini is an unassuming table wine made from grapes grown in different vineyards near Bordeaux.

The name “Petrus Lambertini Major Burdegalensis 1208”, registered as a trademark by the manufacturer, refers to Bordeaux’s first mayor, who in 1208 refused to hand the keys of the city to the besieging forces of the King of Castile, in modern-day Spain.