On the Isle of Wight, where the waters of the River Solent have so far kept the grey squirrel at bay, emergency measures are being taken by the island council to save the 1,500-strong red population.
A supply of squirrel traps has been brought in from the mainland to ensnare greys that have arrived as stowaways on board ferries. A network of lookouts has been established across the island to report sightings of greys to council officers.
Colin Pope, the council's ecology officer, said: "We have had one grey squirrel washed up on the beach on the north side of the island and some have been seen swimming in the Solent, but the distance and the strong currents are too great for them."
The need to protect the Isle of Wight's red squirrels, and a smaller colony on Brownsea Island in Poole Harbour, Dorset, was underlined yesterday by news of the demise of the red squirrel in the Midlands.
There was once an abundant population of reds in the former Royal hunting forest at Cannock Chase in Staffordshire, but ecologists admitted yesterday that it had been wiped out by the grey. Debby Smith, who has been studying squirrels at Cannock Chase since 1993, said: "It is a sad fact that there have been no reliable reports of reds in Cannock Chase since 1994."
The new finding means that there is no longer an established red squirrel population on the English mainland, south of Formby in Merseyside. The populations in the north of England and in Wales are also at grave risk. Since it arrived in Britain in 1876, the grey's numbers have grown to an estimated 2.5 million. By contrast, the red squirrel is down to 160,000, with only 30,000 in England.
In an experiment aimed at reversing the trend, Tony Mitchell-Jones, mammal ecologist at English Nature, is overseeing a project in which 35 reds from the north of England have been reintroduced to woodlands in Thetford, Norfolk. Their food supplies are being protected from the greys, whose numbers are being controlled.
At one point, near the river Tay, the two types of squirrel live in apparent harmony with greys sticking to their broadleafed woodlands and the reds to conifer forest.
But David Bullock, nature conservation adviser at the National Trust, said such conditions were rare. "If the grey ... was ever to establish itself on the Isle of Wight it may well be the demise of the red squirrel there," he said, adding that it could be because greys outcompete reds or because they spread disease. Either way, "we've got to make sure it never happens", he said.
Holding out: The red squirrel has finally disappeared from the Midlands, replaced by the larger grey squirrel, but it is flourishing in the Isle of Wight where residents take emergency measures to eliminate invading greys
Photograph: Martin RugerReuse content