WHEN will the madness end? "I am in blood stepped so far that, should I wade no more, returning were as tedious as to go o'er.'' Presumably, it is something like the thought that spurred Lady Macbeth through multi-murder that now drives the Government's crazy commitment to the mass slaughter of Britain's farm livestock in the increasingly-desperate attempt to defeat foot-and-mouth.

Yes, of course, failure to conquer the disease would - in the capital letters adopted by Maff in defence of the mass cull - bring a "VERY HIGH COST'.' Some £1.2bn in lost exports of livestock, semen, embryos, fresh and frozen meat, and pasteurised milk. But much of that has already been lost and, with compensation to follow, the deficit will take years to make up.

Meanwhile, losses through the collapse of tourism, which earns ten times more than livestock exports, will never be made up. Considering that the cancelled two-night break in the Dales by my wife and I deprived the local economy of the best part of £200, the estimated weekly loss of £250m nationwide does not look exaggerated.

Belatedly, experts are challenging the blanket slaughter. The retired vet who headed the fight against the 1967 outbreak in Shropshire, says: "The cost of losing livestock exports from the ending of our disease-free status would be far lower than the price we would pay for losing a large part of our cattle herd." Together with other veterans of the 1967 outbreak, he insists that mass slaughter, conceived when herds were small and animals were bought and sold only locally, is no longer "appropriate'' - the word I used two weeks ago.

What needs to be in capital letters is a warning that Britain's catastrophe could easily happen elsewhere. For, despite criticism that the Government didn't act quickly enough or firmly enough, the truth is that action has been swift and seemingly drastic at each point. Remember, the NFU actually criticised the early countryside ban on the movement of livestock, which was then eased.

If foot-and-mouth were a form of Black Death, the mayhem might be justified. But it is not. A former colonial farmer now living in Ryedale has reported his experience of an outbreak in Kenya. "All cattle over six months survived, and 90 per cent of the calves," he said. "If the grazing was lush, the condition of the cattle could barely be noticed. Milk production was halved for about a week. The sheep did not show any ill effects. It was our practice to ensure the whole herd got it quickly, so we put down extra salt licks and made sure the fit animals followed the infected ones.''

This aside, there is the moral question. Who is not sickened by the scenes of burning and now the digging of Belsen-like pits to be filled by half a million animals? NFU President Ben Gill says the plight of his members wrenches his guts. Quite right. But millions of us feel in our guts that this mass destruction of farm animals, many healthy and all victims of our folly, is not right. Animals must be treated as more than machines for producing food.

Recognising that a repeat of this catastrophe cannot be contemplated, the Government proposes a ban on swill and restrictions on animal movements. But the disease will at some point breach these defences, perhaps because the rules are disobeyed.

While animals die and the rural economy buckles, the EU holds stocks of millions of doses of vaccine against the present strain of the virus - cost per injection 30p. If this isn't mad, what is?

Our British tragedy demonstrates a worldwide need for routine vaccination. The first item on the Radio 4 news last Sunday morning was the arrival of the troops in Cumbria to organise the mass slaughter. The next item was the reintroduction of the routine vaccination of children against TB.

Why don't we just shoot the infected kids instead?