A rare delicacy from the salad days of ancient Egypt is being grown and marketed at Munsley Court Farm.

Orders have come from as far away as Geneva, even at £150 a kilo - making it "the most expensive vegetable in the world".

Hop asparagus may also be the oldest cultivated root vegetable in the world and now it is only harvested in four locations.

Entrepreneur Mark Berry, who is marketing the Munsley product, said that the crop growing on a local farm had been formally identified as the "right" kind of hop asparagus by Washington DC expert Martin Puterbaugh.

Mr Puterbaugh has just returned to his farm in the USA, having stayed for three weeks as the guest of hop farmers, the Robinson family, who own Munsley Court Farm.

Mr Berry said: "We don't know the full extent of what we have and we have only two weeks to harvest it."

Already, top London-based chef Anton Mosimann has placed an order for Munsley's hop asparagus.

Mr Berry said: "He has been struggling to find some for his Geneva restaurant".

He explained that only certain varieties of hops were suitable for the growing of hop asparagus.

Hop expert Derek Wareham, NFU advisor and former secretary of the Association of the Growers of the New Varieties of Hops, said: "I grew it one year, about 15 years ago, when I was the manager of Brierley Court Hop Farm, near Leominster.

"The hops in the spring throw 20 or 30 shoots and you only need half a dozen. It's a delicacy, the hop shoot, about six to nine inches long, cut off just below the ground with a knife.

"It's almost a miniature asparagus, about a third of the diameter of asparagus. It needs to be £150 a kilo, as it involves a lot of hard work."

The variety Mr Wareham used, Wye Challenger, has since been decimated by a hop disease. Mr Berry declined to say which hop variety was giving hop asparagus at Munsley Court Farm.