Though autumn is happily still some way off, we’ve already reached that stage in the shepherd’s calendar when full-grown lambs loud bleat from hilly bourn. In fact they now look bigger than their mothers. The easiest way of differentiating the ewes from the lambs is that the latter still have their fleeces while the former are shorn and look thoroughly careworn and knackered from having to feed their demanding and needy adolescents long after it’s strictly necessary.

What’s rather spoiling my nature notes at the moment, though, is the nagging fear that next time I venture out into the fields on my morning walk with the dog, our pastoral idyll will have been reduced to a bloody shambles of discarded entrails and severed heads. A gang of professional sheep rustlers has been stalking our county — and all the local farmers are worried that we’re going to be hit next.

I’ve spoken to a couple of the victims, who prefer to remain anonymous. John, a Warwickshire farmer whose flocks have been attacked on four separate occasions, had a particularly horrible experience in April when 18 of his ewes and one lamb were slaughtered in the fields where they stood. ‘A lot of the lambs were still suckling and I found them the next morning bleating next to what was left of their mothers. It was very upsetting.’

Usually the gangs strike when there’s a full moon. And they’re clearly very well organised. ‘They’re rife round us,’ says another victim, Jason, who recently had 19 lambs taken in one night. ‘It’s not easy rounding up 150 sheep in a 20-acre field but that’s what they did — I reckon they must have had a dog. They ran them into a corner, pulled them up with wire on to the branch of a tree, cut their throats and hung them up and dressed them on the spot, took away the carcasses and left the waste.’

Even though it’s an unpleasant thing to find — just the heads, still attached to the fleece, and the guts, all swarming with flies — the gangs are impressively professional. ‘I’m a slaughterman myself and I can tell these people know what they’re doing,’ says Jason. ‘They do as good a job as you’d find in an abattoir.’

So far in the Midlands this year, more than 100 sheep have been butchered in the fields. ‘They’re definitely stolen to order,’ says Jason. ‘When you’re talking 100 lambs, most butchers couldn’t sell that much in two or three months. These are going straight to someone’s fridge.’

This is rustling on an almost unprecedented scale. Last year, farm animals worth £2.5 million were stolen, according to the insurer NFU Mutual — part of a surge in rural crime which has seen it reach a seven-year high and which last year cost the UK £50 million. ‘In a single generation, country people have seen rural crime change from the opportunist theft of a single lamb to brazen heists of tractors worth over £100,000 and rustlers stealing hundreds of sheep,’ NFU Mutual’s Tim Price told the Guardian.

Who is responsible for this carnage? There have been few arrests, still fewer convictions, but the police do have their suspicions. Last year, nearly 10,000 sheep were stolen by livestock rustlers in England and Wales but this only resulted in one charge by the police. ‘These are horrific crimes being carried out by an organised gang of criminals who appear to have an operation with an outlet to sell this illegally slaughtered and stolen meat,’ said a spokesman for NFU.

The people committing these crimes don’t seem much troubled by the prospect of being caught. ‘We found all sorts of clues they’d left behind,’ says John. ‘Fag ends, fag packets, energy drinks. They clearly took their time and were in no rush. Well it’s not like anyone was going to stop them, was it? Maybe six men and a dog in the dead of night, all armed with sharp knives…’

When I lived in London, someone was shot right on my doorstep, while another was given one of those so-called ‘life–changing injuries’ — shot in the balls, I think — having had the temerity to wish a friendly good day to a passing gangster. But you accept that sort of thing in the Big Smoke — ‘part and parcel of living in the big city’, as some pillock once said. They become one-upmanship anecdotes to demonstrate just how edgy and real a thug life you are living in your £1 million-plus mansion.

In the country, though, these crimes feel more invasive, upsetting and personal. You move to the sticks to escape all that ugly stuff, to retreat to a better, more civilised world where it’s still safe to leave your doors unlocked and no one’s going to shoot you, except by accident when they pepper you with shot and then apologise profusely afterwards with a case of decent claret.

The other day, when I went for a swim in one of the lakes on the estate, I particularly resented being warned off by the water bailiff — not because it annoys the anglers, though of course it does, but because an eastern European gang had put out nets to catch the carp and there was a danger I might get caught in them and drown.

Whatever rules these livestock rustlers play by, it’s certainly not cricket. Maybe it’s time to revive the old country tradition of man traps.