Farmers may soon have to undergo training in the use of rat poisons amid concerns from wildlife groups that their improper use is putting wildlife, including listed species, at risk.

Studies have claimed rat poison is toxic to non-target species including stoats, barn owls, red kites and kestrels that inadvertently ingest these chemicals when eating poisoned rodents.

Rodenticides can currently be bought and used without any formal training, but regulations to change that are now being considered as a result of reclassification of second-generation anticoagulant rodenticides (SGARs) by the EU.

The EU risk assessment found SGARs are so toxic they should not be used at all, but as rats have built up resistance to first-generation anticoagulants, it was recognised a scheme had to be put in place to allow their use to control such pests.

The European Commission recognises that member states face different challenges in managing rodent infestations, that they will have different policies and infrastructures in place, different environmental issues, and are likely to take different approaches to the control of their use.

A spokeswoman for the Health and Safety Executive said: "While the use of rodent poison is necessary in some circumstances, we are aware of concerns about the risk this can pose to wildlife and especially predatory birds.

"We have asked the Campaign for Responsible Rodenticide Use to develop proposals for an industry-led stewardship regime to ensure these poisons are used responsibly. We are in the final stages of agreeing what the stewardship programme could look like."

Under proposals being considered, farmers will have to pass a basic training course to apply SGARs on farms. Only certified users will be allowed to buy larger packs for "professional use against rats and mice".

Anyone with experience of them will know the term "dirty rat" is accurate. But while we in the West find them repulsive, they are a dietary staple in other parts of the world. Indeed, rats are farmed commercially as an exotic delicacy in North India, while in the traditional cultures of the Hawaiians and the Polynesian, rat was an everyday food for commoners.

Rats can cause substantial food losses, especially in developing countries. They also spread diseases like Leptospirosis (Weil's disease), Toxoplasmosis and Campylobacter to man, as well as diseases like ­classical swine fever and foot-and-mouth disease among farm animals.

Apart from the feed they waste and the diseases they spread, there are other good reasons to keep farm buildings rat-free. Although polypropylene string is tasteless and of no nutritive value, rats will gnaw through it in a stack of bales.

Jute sackcloth or paper bags are other targets for rats to gnaw holes in. They will also tackle timber, mortar and even electric cables. I wonder how many farm fires have been started by electrical faults as a result of rat-damaged cables?

Plagues of rats used to infest the stacks of oats and wheat sheaves in days gone by. When the travelling threshing mill came, a low net was erected around the stack to prevent the rats escaping, and a few terriers were put in.

As the day's threshing wore on the enclosed area became a mayhem of barking and squealing, mingled with the excited shouts from young lads armed with sticks. Woe betide those who hadn't bothered to tie the bottom of their trouser legs to prevent frightened rats using them as a bolt hole!

Rats always sent a shiver down my spine. Well do I remember the time when I was a young lad and a scurrying rat fall off an overhead rafter and landed on the back of my neck. From that day on, I always banged on the barn door with my fist a couple of times to alert the rats of my presence. Only when the scampering of little feet on loft floorboards had subsided did I enter.

The Scottish Quality ­Cereals Assurance Scheme has done a wonderful job of eliminating the infestations of rats and the resultant rat-dirt that used to occur in stored grain on some farms.

The cereal growers' main defence against these pests are anti-coagulant rodenticides which make up 95 per cent of all rodent control. So it is important the proposed new regulations on their use are practical.