An application has been made to reintroduce the lynx to the British countryside for the first time in more than 1,000 years, on a trial basis.
The Lynx UK Trust has submitted an application to Natural England to carry out a trial reintroduction of six Eurasian lynx in the Kielder Forest region of Northumberland.
The trust said it is the first time an application has ever been made in the UK for this species or any other apex predator.
Last year, the trust announced plans to explore the possibility of bringing the Eurasian lynx back into the British ecosystem.
It said an international team of experts have spent the last year planning the reintroduction, consulting with national bodies, studying potential release sites and consulting with local communities and businesses.
Their findings have now been submitted to Natural England, which is the statutory agency responsible for licensing species reintroductions in England.
The trust said that while any release would take place in England, the lynx may cross the border into Scotland and, as such, Scottish Natural Heritage is also being kept fully informed of all details of the application.
If permission is given, four females and two males will be reintroduced in the Kielder Forest region for a five year period, wearing satellite collars to monitor their movements.
The cats will come from healthy wild populations in Europe and be subject to full veterinary screening.
The trust said the animals would be intently studied and the information gathered would be used to decide whether a full reintroduction can be carried out with more individuals across a wider area.
It said much of Scotland has often been highlighted as having a huge potential for lynx habitat.
The chief scientific adviser on the project, Dr Paul O'Donoghue, said: "Tens of thousands of man-hours of work by a huge team of people have gone into consultations shaping this final application which marks a significant milestone in the history of UK conservation - potentially the first return of an extinct predator, which could prove to be a really keystone species for our ecosystem."
Dr O'Donoghue said the reintroduction of the lynx could bring economic benefits to the Kielder region, suggesting it could be known as "the kingdom of the lynx", a unique eco-tourism destination in the middle of Britain.
He said his team has had positive feedback from local businesses with the Angler's Arms pub, in Kielder Village, already sporting a life-size replica lynx above the bar.
He said: "We've now reached a point where we feel every piece of research has been done, every concern that can be raised has been raised, and the only way to move truly forward is with an intensively monitored trial reintroduction of a small number of cats. That can tell us exactly how suitable the lynx would be for a larger reintroduction."
The trust said lynx were probably wiped out in Britain about 1,300 years ago by fur-hunting. It said it has left an absence of medium-sized cats which has contributed to an over-population of roe deer.
Successful reintroductions in places like Germany, France and Switzerland mean there are now more than 10,000 lynx in Europe.
The trust said there are no recordings of attacks on humans by healthy, wild Eurasian lynx anywhere in the world. It also says the animals have a very low impact on livestock with lynx in Europe killing, on average, less than one sheep every two years.
Last year, Scotland's Environment Secretary pledged that no reintroductions would go ahead without "full consultation".
Roseanna Cunningham said then that farmers and crofters had "serious concerns" about the trust's proposals for the Kielder Forest.