A group of squirrels unique to Cumbria could become extinct in the next 20 years, a leading biologist has warned.
Red squirrels are under threat in the UK from grey squirrels
Dr Peter Lurz, of Newcastle University, has identified a unique type of the species, different from any other in Britain or the Continent.
There are less than 1,000 of the rare Cumbrian reds in the Lake District.
The reds should be put into a captive breeding programme to ensure their survival and a cull of grey squirrels should be considered, Dr Lurz said.
The biologist said the Cumbrian red squirrel was important because more genetically diverse species were less likely to die out.
Cumbria, along with the North East of England and parts of Scotland, is one of the last strongholds of the red squirrel in the UK.
Research has shown reds have coped better with man-made forests, such as Northumberland's Kielder Forest, whereas greys thrive in broad-leaf woods more often found in the Lakes.
Dr Lurz said: "Although we applaud the current conservation efforts to build refuges for the red squirrels, we think these may not be enough.
"A captive breeding programme needs to be introduced as an additional conservation measure, just in case the refuge programme does not work.
"This will guarantee these unique animals are not lost forever."