RSPB Scotland have criticised the Crown Office after charges against a gamekeeper were dropped because video footage of him apparently preparing an illegal trap to kill birds of prey was deemed inadmissible in court.

Staff from the charity had filmed Craig Graham from Brewlands in Angus seemingly setting a “pole trap” designed to snap shut and break the legs of raptors. The barbaric traps were outlawed in 1904.

The birds are protected by law, but can cause difficulties for game- keepers and land managers by attacking smaller birds, such as grouse, which are being reared for shooting.

RSPB staff had discovered the trap in Brewlands on top of a pheasant carcass. With no phone signal to allow them to contact police, they made the trap safe and then placed a video camera pointing towards it.

A few days later the organisation’s staff and a police wildlife crime officer returned to the scene to find the trap had been reset.

The footage recorded allegedly showed Graham resetting the trap. He was subsequently charged him with four offences under the Wildlife and Countryside Act 1981. Police sent a report to the procurator fiscal, who marked the case for prosecution.

Graham pleaded not guilty, and after six hearings, the trial was due to start on Monday. On Thursday, with little warning, the RSPB were told the Crown had dropped the case.

It is the second time in less than a week that prosecutors have dropped a case against a gamekeeper despite video footage.

Stanley Gordon, from Cabrach in Moray, was charged with illegally killing a hen harrier in Moray, after RSPB video footage appeared to show him shooting the bird in June 2013. Gordon always denied illegally killing the bird. In both cases the Crown Office said video evidence was not admissible to the court because it was filmed for the purposes of gathering evidence.

The RSPB believes that prosec-utors in the two most recent cases should have allowed the courts to decide whether the footage was admissible rather than pulling out of the prosecution.

RSPB Scotland’s head of species and land management, Duncan Orr-Ewing, said: “For one case, where there was excellent video evidence to support the prosecution, to be discontinued inexplicably by the Crown Office so close to the trial was baffling.

“For a second case to be discontinued, again with no explanation, and without the opportunity for the evidence to be tested in court, is deeply concerning, and significantly undermines our confidence in the ability of Scotland’s justice system to bear down on the criminals who continue to target our protected birds of prey.”

A Crown Office spokesman said: “Discussions have taken place over a number of years with the RSPB about the admissibility of evidence obtained through the use of covert surveillance. The Crown has consistently made clear the limitations which the law places on the admissibility of evidence which has been obtained irregularly.

“The Crown is committed to the rigorous, fair and independent prosecution of crime, including wildlife and environmental crime. It has a specialist unit dedicated to the prosecution of wildlife and environmental crime, acting under the direction, as required, of a senior advocate depute.

A spokesman for the Scottish Government said: “We take our responsibility to protect wildlife very seriously, and have introduced a range of measures designed to tackle the illegal persecution of birds of prey in recent years.

“Decisions about the prosecution of crime are, of course, decisions for the Crown Office.

“We have been clear that we will bring forward further measures to deal with wildlife crime when we judge it to be required, including, potentially, further regulation of those areas and activities that are threatening raptor species in Scotland.”