Prime Minister Gordon Brown has given his assurance to the National Farmers' Union that he will not stand by and let retailers exploit the foot and mouth outbreak. The farming industry feared the worst when the foot and mouth virus was discovered on a farm in Normandy, near Guildford, Surrey, last Friday. A full-scale operation to stop the spread of the disease was immediately thrown into operation and included a complete ban on the movement of all livestock across mainland Britain for six days. Despite animals on a third farm within the six-mile surveillance zone showing signs of the disease, restrictions on livestock movement outside the zone were lifted at midnight on Wednesday, As The Grocer went to press, the NFU was breathing a sigh of relief that the outbreak appeared to be under control. By Thursday, 576 animals had been slaughtered, a fraction compared with the six and a half million destroyed in the nine-month 2001 outbreak. The NFU had held emergency meetings with Brown earlier in the week. "We expressed our concern that the supply chain could take advantage of the situation and lower the price paid to farmers," said Peter King, NFU chief livestock adviser, referring to fears of a repeat of what happened in 2001. After slaughtering resumed in 2001 there was an immediate 15-25p/dwkg slump in finished cattle prices. King said: "Although retailers have been quick to reassure us there would be no abuse of power, Brown pledged to speak to each retailer about fair pricing and hold them to it." Asda, Sainsbury's and Tesco all promised to support British farmers on price. All three also said there should be no problem in sourcing British meat going forward. An Asda spokeswoman said availability had held up throughout the movement ban as it was well-stocked in anticipation of blistering hot weather and meat sales were up 5% at the weekend. Sainsbury's, which stocks 80% British beef and nearly 100% British lamb and pork, also said it had good availability across all stores. "Now that slaughtering will be recommencing, there will be no changes to our sourcing policy," said a Sainsbury's spokeswoman. Shopper confidence in British meat remained high. In a vox pop of 30 Sains­bury's and Tesco customers, The Grocer found strong support for both farmers and the government. The vast majority of shoppers, 87%, said they would still buy meat. The plight of farmers was the prominent concern for 47%. However, only 17% were willing to pay extra to support them. Retailers and the NFU also said they had been impressed by Defra's hand­ling of the crisis this week. However, there was confusion for processed food manufacturers who were legally allowed to export, but were not given the proper certification. The lack of documentation meant some manufacturers had exports turned away at port. They said government agencies failed to provide clear guidance. "Although the lessons of 2001-2 appear to have been learned in respect of managing the outbreaks on the farms, we were disappointed at the slow response in other parts of the supply chain," said a Greencore Group spokesman.