Experts believe that hormones, taken from the brains of slaughterhouse carcasses, were injected into cows in a bid to create a new breed of super-cattle.
But the experiment - carried out in the Eighties - backfired. The hormones, extracted from pituitary glands, were transmitted in an agent that spread mad cow disease and eventually infected humans as new variant Creutzfeldt-Jakob Disease (nvCJD).
Twenty years ago a similar use of human growth hormone, extracted from the pituitary glands of cadavers and given to children with congenital dwarfism, was shown to have spread CJD among humans.
'The theory is simple,' said Dr Anne Maddocks, a retired senior medical scientist who specialised in infection control at St Mary's Hospital in London. 'The promiscuous use of pituitary hormones in cattle led to BSE in the same way that they led to CJD in humans. The timing of the deaths in cattle and humans who were exposed to pituitary hormones is very compelling.'
Maddocks has a spent year investigating the theory. It overturns previous ideas that blamed the epidemic on changes in the preparation of sheep carcasses infected with the brain disease scrapie, which were fed to cattle. Maddocks is backed by Professor Malcolm Ferguson-Smith, an award-winning Cambridge University scientist on the Government's BSE inquiry team.
Evidence supplied separately by Joanna Wheatley, a former ICI researcher and now an organic beef farmer, also supports the theory. Wheatley says abattoirs were selling pituitary glands to vets and researchers. Cows then got the disease through contaminated brain extract in their hormone injections. Infected cattle were 'recycled' back into the national herd when carcasses were used in feed or bovine medicine.
The theory is also supported by David Brody, the lawyer acting for families of victims of the BSE-related nvCJD, who are suing the Government. Brody also represents families of those who died from CJD after receiving growth hormone treatment.
'One has to take this theory very seriously indeed,' he said. 'There is a striking resonance to the timing of events and the thinking behind them, and the similarities suggest that serious questions need to be answered.'
A spokesman for Ministry of Agriculture refused to be drawn: 'It is a theory being considered, but it is only a theory.'
Although the ban on British beef exports was lifted in Europe last week, BSE specialists warn that nvCJD could still kill millions of people. Sir John Pattison, the chairman of SEAC, the government's scientific advisory body on BSE, told the inquiry into the epidemic that it would take a decade to know the full impact of the crisis.
'We, as a population, are in deep trouble,' he said. 'That is why the range of possible numbers of variant CJD still goes from something not very different from the numbers we have at the moment to six or seven figure numbers.'
His remarks led another SEAC member, David Pepper, to warn the inquiry that the chance of such comments causing 'alarm and despondency and maybe even worse are quite high'.
The year-old inquiry into Britain's BSE epidemic has uncovered a tale of rivalry between Whitehall departments, inadequate hygiene enforcement in slaughterhouses and breakdowns in communications between Ministers and civil servants.
The scandal has seriously undermined the public's faith in the food industry and in government regulatory bodies, and is blamed by many for laying the groundwork for popular public protests against genetically modified crops.
In another sign that scientists are still in the dark over BSE, a new warning has been issued by another scientist advising the Government - Professor John Collinge - suggesting that people having their tonsils and appendix out are at risk of contracting nvCJD.
This is because the disease has been found in these parts of the body and can be spread through surgical instruments, he warns.
The 80-year countdown
1920 Creutzfeldt publishes report of a case of 'Creutzfeldt Disease'
1921 Jakob reports four cases of what became known as CJD
1956 Pituitary hormones are first used to treat infertile women
1970 Growth hormone treatment starts in earnest to help children with stunted growth
1976 Professor Gajdusek PIC wins the Nobel prize for proving that CJD can be transmitted via brain tissue
1976 Health Department warns that growth hormones can lead to CJD
1985 Cow 133 dies
1985 Alison Ley dies from CJD after receiving growth hormones, as do three American children
1987 Government's chief vet informs Ministers of a new spongiform disease in cattle
1988 Government prohibits use of certain foods for cattlefeed
1988 Government announces slaughter policy
1989 Four Australian women die from CJD after receiving pituitary hormones during infertility treatment
1989 EC bans certain cattle exports
1990 Chief Medical Officer gives assurance that beef is safe. John Gummer feeds it to his daughter
1993 British women warned hormone treatment could be fatal
1995 Stephen Churchill, 19, dies, the first known victim of a new variant of CJD linked to BSE, and the first of three cases that year
1996 EC bans exports of British beef
1998 High court rules Government negligent in allowing growth hormone treatment to continue
1998 BSE Inquiry opens under Lord Phillips. Report due in March 2000