Olive prices are set to soar this year because of poor judgement by producers in the Mediterranean.

Prices in contracts with UK traders have risen as much as 10% already, with a strong chance of further rises in the summer. Spanish supplies are the worst hit, while Greek olives are barely affected.

It's all because olive growers left their unripe green olives on the tree too long, according to Henry Amar, managing director of leading importer RH Amar.

The company owns the UK rights to market-leading olive brand Crespo as well as Gaea and has its own brand, Cooks & Co.

"Last year table olive producers realised they could make more money selling to the crushers to make oil because of the size of the crop," he said.

"This year they tried the same tactic, but by the time they realised oil prices were lower, they'd left the olives on the trees too long."

As a result, quality is much lower than usual and there are fewer green olives available. The table crop is notoriously delicate and has to be hand-picked.

It means the industry is now in the extraordinary position of seeing oil prices fall while table olive prices rise, Amar said.

Usually importers agree a price for the entire season, but because of the uncertainty this year they have only guaranteed prices until June. "We don't know that prices will definitely go up, but importers are keeping their powder dry just in case," he added.

However, market prospects were still bright, even if prices did rise, Amar claimed. "I don't think it's going to have any impact on consumption. Household penetration of olives is only 17%, so there's a huge market to go for."

Last year, volumes rose 10% but value sales rose 25% to some £40m as consumers traded up to premium offers.

"They are buying more expensive varieties as well as olives with gourmet stuffing, such as sun-dried tomatoes."