A tree disease which has destroyed entire forests in America is spreading in the South West.
Death is inevitable if the fungus strikes (Image: Forestry Commission)
Another case of the Sudden Oak Death fungus is suspected at the Lost Gardens of Heligan in Cornwall.
There are three more cases in the county, making the region one of the worst affected in Britain.
A spokesman from the Department for the Environment and Rural Affairs (Defra) said they were confident they could control the disease.
The fungus, known as Phytophthora ramorum, has killed 80% of one oak species in the western US.
There is no known cure for the disease, which kills the trees' bark and is thought liable to affect other species.
It was discovered last year in viburnum plants in British garden centres, and there have been hundreds of subsequent outbreaks in plant nurseries and in some wild rhododendrons.
But the disease did not appear in a British tree until November, when it was identified in a southern red oak in Sussex - a tree imported from the US.
One other tree at Heligan and two more on nearby land are also suspected of having the disease.
Scientists are not sure how the disease spreads, but they think it is probably through water, with rain falling unto a tree or shrub and then splashing onto its neighbour.
The South West is one of the worst affected regions, with more than 200 outbreaks in other plant life.
Defra has previously ordered Heligan to burn rhododendrons which were infected.
Peter Stafford of the Lost Gardens of Heligan said: "It's a concern having it here because it's an unknown quantity.
"We could be asked to have serious pruning, or worse - wholesale removal of trees or shrubs."
The great worry is the disease's spread to trees.
Native English oak does not seem vulnerable. It may be protected by its thick bark. But other popular trees are thought susceptible, such as beeches, conifers, spruces and firs.
A Defra spokesman said more staff were being drafted in to tackle the problem and they were confident they could keep the disease under control.