Gavin Strang, Labour's agriculture spokesman, claimed that some animal- feed manufacturers may have used the same equipment to mix both cattle feed and pig feed. Until March, the latter was allowed to include bovine offals, banned in cattle feed since 1988.
Dr Strang said it may be one of the reasons why a total of 27,000 cattle born since 1988 have contracted the disease. ''The animal-feed manufacturers may have mixed the two by accident,'' he told the Independent.
The disclosure came as the pounds 550m scheme to rid the food chain of cattle over 30 months old still showed no signs of getting under way. And Michael Heseltine, Deputy Prime Minister, said publicly for the first time that the beef crisis was "and still remains the most difficult political issue I have ever seen a government face".
Dr Strang, who is calling for an inquiry into whether cattle have been given contaminated feed, said he was concerned that two-thirds of BSE cases reported in the first three months of this year involved cows born since the ban. ''Everyone accepts that the feed is the major cause, if not the only cause. We have really got to get to the bottom of this,'' he said.
However, the Ministry of Agriculture warned that his remarks were irresponsible and insisted that every measure was being taken to ensure feed was free of contamination.
The controversy stems from the measures introduced in 1988 to keep specified bovine offals out of the food chain. Animal-feed manufacturers were banned from boiling down offals into protein for cattle feed. However, there was no restriction on their use in pig and poultry feed, which is often produced at the same plants as cattle feed, and farmers were not prevented from giving their remaining stocks to their cattle.
It was not until 28 March this year that manufacturers were prohibited from using any mammalian meat or bonemeal in any feed for farm animals. The use of feed containing the products was then banned with effect from 4 April.
The concern now is that farmers have unwittingly given contaminated feed to their livestock because the same mixers may have been used for pig feed as well as cattle feed, although manufacturers are supposed to wash down the mixers between each production run under Ministry of Agriculture rules.
Sir David Naish, the NFU president, admitted: ''These animals born after the ban have nearly without doubt been exposed to contaminated feed. If a tiny bit of the original contaminated material had remained in those mixers that could well have been where the contamination came from. That is not allowed any more, nor should it be.''
Tony Baldry, Minister of State at the Agriculture Department, accused Dr Strang of hyping the issue. ''I am not sure that anything Gavin has asked for is actually going to add to our total knowledge on this issue.''
Meanwhile, EU agriculture ministers meeting in southern Italy last night feared that talks on how free-trade pacts could ruin EU farmers would be overshadowed by the beef crisis.
The Agriculture Minister, Douglas Hogg, is likely to lobby discreetly for a lifting of the worldwide ban imposed on British beef exports, even though it is not on the agenda.
On Tuesday, Mr Baldry is due to meet representatives from all sectors of the beef industry in a bid to break the deadlock in the scheme aimed at disposing of cattle over 30 months old. Apart from 100 cattle slaughtered in Scotland on Friday, there are no signs that the cull has begun, despite Government assurances that it has.Reuse content