Efforts to save endangered red squirrels are set to receive a £1.2 million boost from the Heritage Lottery Fund.
Funding will go to support a four-year programme to secure the future of the native red, immortalised as "Squirrel Nutkin" by Beatrix Potter, across the UK.
Red squirrels have vanished from most of England and Wales and from parts of Northern Ireland and Scotland as a result of the impact of non-native grey squirrels, introduced from America in the 19th century.
Grey squirrels out-compete the reds for resources and carry a squirrelpox disease that is fatal to the native species.
The Red Squirrels United coalition, led by The Wildlife Trusts, will work directly in England, Wales and Northern Ireland, and with the Saving Scotland's Red Squirrels partnership in cross-border action in a bid to reverse the fortunes of the charismatic mammal.
The project will involve culling grey squirrels to preserve existing areas which are free of the non-native species, for example on the island of Anglesey and in Kielder Forest, and protect conifer woodland habitat where red squirrels thrive and greys do not.
It will extend existing red squirrel "protection zones" in mid-Wales and Merseyside and take a whole country approach to preserving the native reds in Northern Ireland.
Community-based rapid response teams will be set up involving 1,250 volunteers trained to protect key red squirrel populations threatened by coming into contact with greys, with measures to humanely trap and shoot the grey squirrels.
The scheme's backers said all conservation work to protect the red squirrels would be rigorously monitored and would contribute to scientific research.
Stehpanie Hilborne, chief executive of The Wildlife Trusts, said: "Our beautiful native red squirrels deserve our protection in every part of the UK where they can still thrive.
"This investment will allow us to unite hundreds of people championing this charismatic creature into one UK force for good. It will build on decades of hard work and passionate commitment."
Tom Tew, trustee at the Heritage Lottery Fund, said: "The ongoing plight of the red squirrel is perhaps one of the most alarming and well-known conservation issues that this country has seen.
"It's great to see such strong co-operation between conservation organisations which now, thanks to National Lottery players, have a great opportunity to capitalise on all the local work and build a co-ordinated, national response to the threats faced by this endangered species."