Up to 38,000 mountain hares are killed a year in Scotland, it has been revealed, as a charity blamed mass culls by shooting estates and called for an end to 'persecution' of the species.

Onekind, the Scottish animal campaigns charity, also accused Scottish Natural Heritage of conspiring to keep the issue under wraps, and hold ministers back from taking action over the issue.

The charity said the number of animals killed has never previously been monitored, but was estimated to be in the tens of thousands.

However a Freedom of Information (FoI) request by The Ferret website has revealed figures compiled for the Scottish Government by Scottish Natural Heritage (SNH) which show the average annual death toll to be 25,961, although they peaked at 37,681, four years ago and the most recent figures, for 2015, show 26,952 were killed that year.

The Scottish Government previously published a joint statement with representatives of the shooting industry calling for "voluntary restraint" in the face of large scale culls. But Onekind claims the figures show this is not working and are warning of "significant declines" in numbers of the species in parts of the country.

However a spokesman for the Scottish Gamekeepers Association disputed this and said the figures did not show evidence of "unsustainable management."

Harry Huyton, Director of OneKind, said: “This new data shows that large-scale mountain hare killing is a routine part of grouse moor management in Scotland, and Scottish Natural Heritage knows it.

"Scottish Natural Heritage should be leading the way when it comes to protecting wildlife, but instead it appears to be holding the Scottish Government back from taking action against unregulated mountain hare killing.”

The documents uncovered by The Ferret show that in February 2017, the Scottish Government asked Scottish Natural Heritage (SNH) for advice on how to monitor efforts to control mountain hares.

The agency concluded no regulatory action was needed.

Mr Hutton added: “Evidence of significant declines in mountain hares in parts of Scotland is being disregarded, and voluntary solutions are being pursued when the evidence that this is not working is plain for all to see.

"Our knowledge of how the mountain hare population is faring in Scotland is imperfect, but there is cause for concern and no evidence that large-scale culls are necessary in anyway. The presumption should always be in favour of protecting native wildlife, not inaction.”

However David Noble, chairman of the Game and Wildlife Conservation Trust, an average of 25,000 culled per year represented only seven per cent of the population, which he described as "a very sustainable harvest."

A spokesman for the Scottish Gamekeepers Association said: “It is our understanding that there is evidence in circulation which disproves local population decline in north east Scotland.

“Hares are controlled across different landscapes because, amongst other things, they can cause serious ecological damage at high densities."

A Scottish Government spokeswoman said: “We have been clear that we oppose any level of culling which threatens the conservation status of Scotland’s mountain hares and are discussing the evidence and next steps with land managers, as well as conservation and animal welfare organisations. It is important to recognise mountain hare numbers require to be controlled in specific circumstances, such as to protect native woodlands or commercial forestry.”

Eileen Stuart, Head of Policy and Advice at SNH said: “While there is currently no evidence of a national decline in mountain hares, the surveillance scheme we are starting this winter will give us a better understanding of the distribution and abundance of mountain hares across Scotland.

"There is new data shortly to be published which suggests there may be population declines in some areas.   We need to determine how representative this is of a wider, national, picture. In the meantime, we continue to urge estates to exercise restraint on mountain hare management until we have a better understanding of population numbers”