From the Welsh hills, the Cheshire plain and backwaters such as Burgh- le-Marsh in Lincolnshire, they took a rare day off from the farm to demonstrate their anger at the Government's handling of bovine spongiform encephalopathy (BSE).
David Redgate, of Brinsley in Nottinghamshire, was typical. After losing thousands of pounds on beef bulls sold at auction he had come to London to demand a change of policy and the resignation of Douglas Hogg, the Minister of Agriculture.
"Maybe it is a token gesture, but after what farmers have been through I felt we had to come and complain," he said. Glancing across the stocky men with weathered faces who filled Westminster Central Hall, he added that it looked as if most families had "sent Dad to make the protest while the sons stay at home to do the work".
There was a groan from the hall when Sir David Naish, president of the National Farmers' Union, alerted farmers to the disclosure of new evidence linking the new strain of Creutzfelt-Jakob disease in humans to BSE in beef.
Farmers had been through "217 days of sheer hell" since 20 March, when ministers first announced the probable link, he said. Sir David, who later delivered prime beef to 10 Downing Street, called for more support for the beef industry and hill farmers - hit hard in this autumn's cattle sales - and for a speedier cull of older cattle.
Mr Hogg has promised that the slaughter of cattle over 30 months old will be stepped up to 50,000 a week. Officials expect to hit this target next week but it will take until next March to clear the backlog of condemned animals.
Sir David said he was angry that some traders and dealers had exploited the plight of those caught up in the mismanagement of the scheme. An NFU member from the North-east said renderers and slaughterhouses were holding farmers to ransom. "Spivs, auctioneers and dealers are taking us to the cleaners".
But the message that the farmers most wanted to get home was the imperative of re-opening export markets for their beef. Repeated signals by Mr Hogg that there would be no selective cull of cattle was seen in the rest of Europe as breaking the Florence Agreement on a phased lifting of the export ban, Sir David said.
Underlining the NFU council's extraordinary vote of no confidence in Mr Hogg, he warned: "Let him be in no doubt where he stands with the farming community - at rock bottom."Reuse content