Experts have warned food prices are under further pressure after the price of shipping fuel reached a two-and-a-half year high.

Known as bunkers, shipping fuel prices at Europe's biggest port Rotterdam have risen by 18.5% since the start of the year to $627 per tonne [Mintec 23 February]. Bunkers had not passed the $600 mark since August 2008. The price is of concern to the grocery industry because 99% of food imported to the UK arrives by ship or via the Channel Tunnel, according to Defra.

Instability in the Middle East would continue to inflate prices, warned one commodities analyst. "Shipping is getting a higher profile as people are seeing ships rescuing the distressed and these ships all need fuel," he said.

Rising oil prices and increased seasonal demand for commodities could also see costs spiral. Standard Chartered Bank agricultural commodities analyst Abah Ofon said the grains trade had accelerated as buyers fearing further commodity price hikes looked to build stocks. "It will cause more concern over food inflation as that adds to the cost of commodities," he said.

Last week, shipowner Maersk revealed it was reducing the speed of its tankers to use less fuel and save money. "The shipping sector suffers from the same dependency on oil as cars, domestic heating, road and rail freight," said a British Shipping Chamber spokesman.

This week, RMI, the Independent Petrol Retailers Association, warned the price of unleaded fuel could reach 140ppl at the pumps in April if the scheduled duty increase goes ahead.