Landowners have been accused of breaching an agreement to end the mass killing of mountain hares in the wake of

evidence that hundreds were shot in the Cairngorms last month.

The Sunday Herald has been passed photographs taken near the Lecht mountain pass by the A939 between Cock Bridge and Tomintoul on the afternoon of February 25. They show a pickup truck full of dead hares.

According to an eyewitness, the truck was part of a 20-strong group of armed gamekeepers from several surrounding sporting estates equipped with more than a dozen high-tech off-road vehicles.

Wildlife experts have attacked the cull as “brutal” and “inexplicable”, and demanded an immediate ban on killings. Landowners, however, have dismissed the attacks as “ill-informed and misleading”, insisting that they have not broken any agreement.

The Government wildlife agency Scottish Natural Heritage (SNH) made a joint statement on mountain hares in December 2014 with the landowning groups, Scottish Land and Estates and the Game and Wildlife Conservation Trust. It called for “voluntary restraint on large culls which could jeopardise the conservation status of mountain hares”.

Conservation groups have always feared this would be ineffective. In April 2015, a coalition of 10 groups demanded a three-year ban on all culling until proper safeguards to protect endangered hares were in place.

The photographs were taken by a birdwatcher, who wishes to remain anonymous. There were “hundreds” of dead hares, he said. “They did not like me taking pictures, so I did not hang around.”

Dr Adam Watson, a veteran mountain ecologist and Cairngorm expert, said he was outraged by landowners culling mountain hares. On the grouse moors that he had studied hares had been virtually eradicated by “severe killing”, he said.

“What we now see on the photos and elsewhere is a brutal military-type operation involving several estates and using fast snow scooters and

other machines, which can move faster than the hares. Any that escape this massacre must be traumatised.”

Landowners legally cull hares in the belief it helps protect grouse from disease, and ensures there are more birds available to be shot for sport. But this is rejected by conservation groups.

Jonathan Hughes, chief executive of the Scottish Wildlife Trust, said: “It is very sad that some landowners are clearly not heeding the very sensible call for constraint on large-scale culls of mountain hares.”

Landowning groups insisted culls are necessary where numbers are high. “We are deeply concerned that once again an ill-informed attempt is being made to discredit the legitimate culling of mountain hares,” said Tim Baynes, director of Scottish Land and Estates’ moorland group.

Adam Smith from the Game and Wildlife Conservation Trust in Scotland also argued that it would be wrong to conclude the call for restraint was being ignored.

Without knowing details, it was possible the dead hares in the photos were “part of a sustainable harvest”, he said.

SNH agreed that it was difficult to judge whether the cull was excessive or not. It was aiming to improve its population estimates of mountain hares by 2017, and reiterated its call for “restraint on large-scale culls of mountain hares.”