In ancient times the graceful and agile lynx was known as the “keeper of the secrets” of the forests of Europe.

Threatened by extinction in modern times, it’s secret is well and truly out of the bag now after outrage was sparked when a captive lynx on the run from a Mid Wales zoo was shot dead by a marksman.

The Farmers’ Union of Wales says Ceredigion Council was right to shoot to kill the one-year-old animal, known as Lillith, who was suspected of mauling seven sheep after it leapt from its cage at Borth Wild Animal Kingdom near Aberystwyth towards the end of October.

Yet animal lovers have vented their fury over the shooting decision, which was taken after a farm vet advised there was a risk to the public because Lillith had been spotted in an empty caravan park.

Their views are echoed by a conservation trust based in St Asaph, which has already advanced plans to reintroduce the species into the wild.

The Lynx UK Trust believes the groundswell of anger over the shooting and a second lynx death at the animal zoo will increase support for its campaign.

It believes farmers’ fears are misplaced over wild lynx attacking their livestock.

The conservationists also stress the animals have no track record of attacking humans, although in their natural habitat of forests they can clinically take down much larger deer despite being around only twice the size of a domestic cat.

And it is in a forest setting – Kielder in Northumberland – that the Lynx UK Trust has submitted plans to Natural England for a “rewilding” programme, where six wild lynx would be tracked to see how they settle in a natural environment.

Despite opposition from the farming community, a similar pilot scheme is being lined up for the Scottish Highlands and, possibly in the future, in Wales with the overall aim of returning a sustainable population of lynx to the UK over the next decade.

Dr Paul O’Donoghue has worked with the trust as a chief scientific adviser since it was launched three years ago and has expertise in protecting endangered animals, such as the Scottish Wildcat.

He believes the time is right to bring lynx back to the British Isles after it was hunted out of existence in the 7th century.

The trust points to several successful resettlement projects in other European countries, including the Harz Mountains in Germany where it is estimated lynx tourism generates £12.8 million a year.

Dr O’Donoghue believes similar schemes in the UK could do the same, as well as help control the country’s out-of-control population of deer, who are wild lynx’s natural prey.

“The loss of Lillith was deeply upsetting, but her greatest legacy may be the outpouring of sorrow and concern from people,” he declared.

“Since our project started we have felt there was a will among the public to look into lynx release – we undertook the largest conservation consultation ever in the UK and 92 per cent of the 9,600 responding wanted to see lynx reintroduced.

“We are very confident of getting a licence for Kielder where there would be six lynx, two male and four females, who would be GPS-collared at all times. It would be a trial to see how they settle.”

The trust’s plans have been bitterly opposed, not only by farming unions, but the National Sheep Association (NSA) which accused Lillith the lynx of the sheep attack.

It says Scandinavian sheep farmers have suffered big losses in attacks by single lynx who have developed characteristics of opportunistic hunters.

And with the Kielder proposals in mind, the FUW says the incident should come as a stark warning.

“Given the risk to people and livestock, action to remove such a danger was long overdue.

“Despite being around the size of a sheepdog, an animal like this will routinely kill animals much bigger than itself, and the fact it was used to humans increased the risk it posed to the public,” said an FUW spokesman.

“Had the animal not been allowed to escape in the first place this situation would not have arisen and it seems a number of our member’s livestock would not have been attacked and killed.”

NSA chief executive Phil Stocker said: “This raises questions around the similarity between the proposed release site in Kielder and the area of Wales where this incident took place.

“If the release goes ahead and the lynx population expands in the way it is intended, the species could find its way into Wales years into the future without consultation taking place.”

Yet conservationists believe this is not a valid comparison and point out that Lillith the lynx’s final days were anything but happy as she found herself in unfamiliar terrain in low-lying farmland surrounding Borth.

“Lillith was a captive-raised animal who had never hunted and she escaped in a place that was unsuitable for her,” pointed out Dr O’Donoghue.

“Borth is a seaside town, not a forest, so she was in a poor situation and we can only feel sorry about this tragedy.

“Lynx are never going to attack or kill anyone – but they can be enjoyed in their natural environment.

“The thrill of walking in a forest where there are lynx can be a fantastic feeling. In Germany they call it the “land of the lynx”.

“There are good reasons to bring lynx back to the UK, including tackling the deer population which is literally out of control as well as providing a job boost for struggling rural communities.

“We understand the farmers’ concerns, but it’s been shown lynx will only kill sheep at a rate of 0.4 a year, so how can that be a serious threat to the industry when in the UK over two million sheep die through malnutrition and disease?”

The trust has called for the Borth zoo to be shut down permanently. Owners Dean and Tracy Tweedy, who bought the animal park earlier this year, have said the second lynx, Nilly, died accidentally when she was noosed by a member of staff trying to move her to a new enclosure ahead of a council inspection prompted by Lillith’s escape.

They said in a statement: “When we took over six months ago we knew there were serious issues and the lynx enclosure especially was not fit for purpose.

“Hopefully, we can work with the authorities to bring this place up to code and create a home for these animals that is safe and secure.”

But the Lynx UK Trust’s scientific adviser says he has no sympathy for the owners, who he claims refused his offer of expert help during the search.

“You don’t cram five solitary lynx into a single cage, you don’t leave easily climbed trees in the enclosure and you don’t refuse offers of free help from lynx experts,” added Dr O’Donoghue.

“We do not believe the vast majority of zoos can provide a safe life for captured lynx. These animals roam over 200 square miles, but they are put in an enclosure no bigger than my living room.

“When you see animals in them you feel sad and you question why an animal like Lillith should be in a cage in the first place.

“She was not a beast to be feared. This tragedy compares to the killing of Cecil the Lion.

“Our priority is to bring lynx back with a controlled release, but we can’t ignore what has happened at Borth. UK ‘hobby’ zoos are disasters waiting to happen.”