A TRAGIC betrayal of farmers, that DEFRA in announcing yet another consultation (December 16 ) on TB, proudly announced that they had managed to cull 10,858 badgers this year, at a probable cost of £30 million, including c. £7 on extra policing.

This will have had nil effect in stopping the spread of bovine TB, because the spread has been via bought-in newly infected cattle all along.

So why, and how on earth are farmers so certain that badgers are the problem?

It all goes back to the 1980 Lord Zuckerman Report.

There was clearly still a hidden reservoir of TB in the last intractable southwest pockets of TB. But MAFF vets wrongly ruled out cattle, since they wrongly assumed that only Open Visible Lesion cattle could spread TB.

Just 20 in 1,000 reactors, so cattle-to-cattle and cattle-to badger spread supposedly unimportant.

And cattle must therefore be catching TB from a widespread source in badgers.

But in fact, unlike human TB, cattle do not form “closed” lung lesions, and cattle are infectious at any stage of the disease, going through the newly infected No Visible Lesion to Visible lesion stage, but shedding increases as more lesions develop.

So as Francis pointed out in 1947 in “Bovine TB”, if any cattle with even very slight lesions are left in the herd, spread of TB will be more or less rapid within the herd.

Strikingly after 2001 foot and mouth, with no cattle testing for two years in some herds, 40 per cent of breakdowns had six or more reactors.

Two studies of 105 reactor cattle found that spread was entirely by aerosol spread, particularly by prolonged close contact in barns, so lesions were present in the pulmonary lymph nodes draining the lungs.

And 20 per cent of cases were sputum positive, despite having No Visible lung lesions.

Remarkably farmers do not understand this, cattle test clear before spring turnout, meet those terrible badgers and are riddled with TB almost overnight; whereas in reality it takes six months for new cases with “barn-caught TB” to reach the reactor stage.

And so, true at the low point, cattle controls were so effective about half of herd breakdowns had just the index case.

But no one noticed, the other half had c. 3 reactors/breakdown, so cattle-to-cattle spread WAS still happening, with a modest spillover to a small number of badgers, at the epicentre of the breakdown farm.

There has never been widespread reservoir of badger TB.

Cattle TB is simply an infectious respiratory pneumonia, which if unchecked spreads inexorably within the herd, then to new herd breakdowns, and so throughout the cattle population; nothing to do with badgers after all.

Martin Hancox, ex-government TB Panel

Stroud