Red squirrels are thriving against the odds on one of Britain’s largest estates, after painstaking work by the dedicated of the National Trust.

The population of red squirrels at Wallington in Northumberland almost disappeared entirely in 2011 after grey squirrels moved into the area, bringing with them the deadly squirrel pox virus.

However, the estate is now home to over 150 red squirrels.

Threatened by disease and a loss of habitat, red squirrel numbers have fallen in the UK from approximately 3.5 million and those that remain are constantly under threat from non-native greys. This week marks the beginning of Red Squirrel Awareness Week, designed to highlight the decline.

The project at Wallington has not been plain sailing and invasions of grey squirrels have led to outbreaks of squirrel pox. By responding quickly, red squirrel ranger Glen Graham has helped the population of reds to recover and grow again.

Mr Graham said: "Looking after the reds has become more than a job and it’s the animals and changing seasons which dictate my schedule. I’m delighted with the progress we’ve made here for red squirrels and hopefully, we can emulate this success at other sites across the country. The reds are so popular with tourists and locals alike, and form a key part of the UK’s woodlands landscape."