A cargo of 50,000 tons of British barley has been loaded for shipment to the world's top buyer of the grain, Saudi Arabia, farmers co-operative Openfield said.
The barley was loaded at Portbury Grain Terminal in south-west England.
Britain has a much larger barley crop than usual this year after a wet autumn in 2012 led many farmers to switch from growing winter wheat to spring barley.
The country's farm ministry earlier on Monday estimated this year's UK barley crop at 7.1 million tons, up 29 percent from the prior season.
Britain exported 42,000 tons of barley to Saudi Arabia during the 2012/13 season (July/June), according to customs data.
Saudi Arabia is by far the world's top barley buyer and is expected to import 7.5 million tons in 2013/14, slightly down from 8.0 million tons in the prior season, according to the International Grains Council.
Openfield said some of this year's UK barley surplus has already been shipped to North Africa, principally Tunisia and Libya. A total of 27,500 tons was shipped in Tunisia in 2012/13 but there were no exports to Libya.