Wildlife campaigner Chris Packham has accused Scottish authorities of inconsistency after prosecutors dropped charges against a former gamekeeper accused of illegally shooting a bird of prey.
RSPB Scotland said one of its cameras at Cabrach in Moray recorded evidence suggesting that a hen harrier had been illegally killed in June 2013.
The camera was monitoring the active nest of a breeding pair of hen harriers on the Cabrach Estate, but the Crown Office said the evidence would not be admissible in court.
RSPB Scotland said RSPB video evidence has been used in the successful prosecution of previous wildlife crime cases in Scotland, and Packham said deeming this evidence inadmissible shows a "lack of consistency".
The Springwatch presenter, who said he is "very angry" about the situation, told the Press Association: "I would also like to strike a contrast between evidence of this nature and evidence in other aspects of our lives.
"Imagine a camera had been set up in mine or your back garden to record foxes, because we feed them there.
"And for some bizarre reason - this is entirely hypothetical nonsense - but what we catch are some people building a terrorist device on our camera. Would that be admissible in court do you think? I imagine it would.
"Imagine a CCTV camera, set up in a car park to see if anyone's not parking in the right place or paying their fee, records a murder. Would that be admissible in court? I imagine it would be.
"So, what Scottish government, Scottish courts, the bloody hell is going on here?"
Talking about the footage, he said: "When I saw that footage, which I hadn't seen before because it had been locked up for three years, I was pretty cross. In fact, it ruined my day."
Packham said he and other campaigners are interested in the law being implemented and upheld.
He added: "This was a fantastic opportunity for that law to be implemented and upheld, and it's been taken away from us and we're justifiably upset.
"I can't imagine how the RSPB feel, their investigations team and RSPB Scotland. They must be gutted, to say the least, absolutely gutted. I really feel for them.
"They put in a tremendous amount of time and effort to try and catch these people, and when they catch them red-handed, their evidence is not admissible. I'm angry, I just can't imagine how they feel."
Duncan Orr-Ewing, head of species and land management at RSPB Scotland, said: "We are appalled and extremely frustrated that the court has not been given the opportunity to give a judgment based on this clear footage, and we are perplexed by the inconsistency in approach to these cases that seems to be taken by the Crown Office (COPFS)."
A COPFS spokesman said: "In accordance with the Crown's ongoing duty to keep prosecutions under review, and after carrying out a detailed review of all of the relevant material, Crown Counsel considered that the inevitable conclusion was that RSPB investigators entered the land in question and embarked upon evidence-gathering for the purpose of prosecution.
"Discussions have taken place over a number of years between RSPB and COPFS about the admissibility of evidence obtained through the use of covert surveillance.
"The Crown has consistently made it clear that strict legal tests must be met before evidence which has been obtained irregularly, such as the evidence in this case, is admissible.
"We will continue to have further dialogue with RSPB.
"In the whole circumstances, Crown Counsel concluded that the evidence would not be admissible in court.
"In light of that conclusion, it was entirely appropriate that proceedings were brought to an end."