The supply of anticoagulants has been subject to strict regulation under the UK Stewardship Regime since 1 October and the introduction of strict Point of Sale limitations means less regulated supply routes have now disappeared.

Pest experts say growing numbers of qualified users are being approached to sell part of their own supply as a result.

But they’re warning passing on products to third parties who are not trained and certified is in breach of label conditions – and could land farmers in hot water.

Dee Ward-Thompson, technical manager of the British Pest Control Association, said: “Farmers using anticoagulant rodenticides in their operations must now be officially competent in their use – or be members of an approved farm assurance scheme.

“But those selling or passing on any of their supply must make sure each recipient is also fully compliant.

“Failure to adhere to the requirements may result in the withdrawal of supply – which means they’d be unable to use rodenticides in their business.

“They may also be in breach of the Biocidal Products regulations, which would mean they could also be prosecuted.”

The BPCA is urging farmers to follow the rules carefully and report anyone operating outside the law.

Ms Ward-Thompson added: “The Stewardship scheme is a chance for everyone to demonstrate that anticoagulants can be used safely and effectively.

“These products are among the most effective on the market so it’s crucial to anyone carrying out pest management activities to help ensure they’re not banned completely.

“The only way to avoid that is to abide by the restrictions, so I’d urge farmers to ignore the temptation of selling to neighbours or friends who aren’t certified.

“Anyone who hears of people or companies attempting to sell products without carrying out the necessary checks should notify the Campaign for Responsible Rodenticide Use (CRRU) and the authorisation holder of the products concerned, with full details of the incident.”