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STORY: There were at least 50 tractors, many with Union Jack flags and signs such as "no farmers, no food, no future" in the demonstration that blocked roads in central London for some time.

The farmers are demanding that the government enforce more accurate food labelling and take steps to improve the country's food security.

They also want the government to end trade deals that they say are allowing imports of food produced to standards that would be illegal in Britain and undercut local farmers.

The rally follows protests by farmers across Europe who are angered by competition from cheaper imports and want stricter environmental regulations.