The highest-ever recorded number of poisoned baits for the killing of birds of prey in the same location has been recovered.

However, no-one has been prosecuted over the discovery, sparking fears that wildlife crime is still widespread despite the Scottish Government's pledge of a crackdown.

Analysts from the Scottish Agricultural Science Agency (Sasa) have confirmed that 25 carcasses of rabbits and hares laced with deadly carbofuran were found within a square mile radius in countryside near Greenlaw in Berwickshire, between March and September.

They were discovered on five different occasions over six months, alongside six buzzards, two crows and a magpie which had been poisoned after eating the bait.

But there was no publicity warning about the discoveries, despite the obvious risk to public health from the toxic substance, which was banned in 2001. Nor were there any prosecutions resulting from the find.

It is the large-scale discovery of 25 poisoned baits within such close proximity, and the fact that no-one is being held to account, which has dismayed wildlife crime investigators.

A member of the public first informed Lothian and Borders Police in March 2007 that poisoned baits were being left out in the open air on an estate near Greenlaw.

A search took place but it is understood issues over land ownership may have complicated the operation and no-one was held to account for the poisonings.

The samples were sent to Edinburgh-based Sasa, a government agency, where scientists have now confirmed carcasses were submitted for analysis from the Greenlaw area on five separate occasions during March and September of 2007.

Doreen Graham, spokeswoman for the Scottish Society for the Prevention of Cruelty to Animals, said: "We are concerned at the large number of poisoned baits found at Greenlaw in Berwickshire.

"Carbofuran is an illegal substance and we believe the only people who still have access to quantities of the substance are well aware that they are breaking the law."

A spokesman for the RSPB said: "This staggering level of illegal activity goes to show that poisoning is sadly still considered par for the course by some people in Scotland."

A Scottish Government environment spokesman said yesterday: "We deplore the dangerous and cruel practice of leaving poisoned baits around the Scottish countryside. Investigation of these crimes is a matter for the police."

A Lothian and Borders Police spokeswoman could not give a reason why there had been no publicity issued following the discovery of the poisoned baits but she added the cases were notoriously difficult to prosecute due to the lack of witnesses in remote locations.