Imports of ash trees will be banned from Monday in an attempt to stop the spread of a disease which has devastated them in Europe, it has been announced.
Environment Secretary Owen Paterson said he was "ready to go" with legislation to ban ash imports, which have been blamed for introducing the chalara fraxinea fungus to the UK.
The fungus, which causes leaf loss and crown dieback and can lead to tree death, has wiped out 90% of ash trees in Denmark in seven years and is becoming widespread throughout central Europe.
Ash dieback had previously been identified in nurseries and recently planted sites including a car park, a college campus and a new woodland, but has now been found in the wider environment at sites in East Anglia, increasing fears it could wreak the same kind of damage as Dutch elm disease in the 1970s.
Mr Paterson told the BBC Radio 4 Today programme: "I will bring in a ban on Monday, having discussed this over the weekend with officials and experts.
"I have already prepared the legislation and we are ready to go. The evidence is clearly there. There will be a ban on Monday."
The president of the Country Land and Business Association, Harry Cotterell, welcomed the import ban, but said it may not be enough to stop an epidemic.
With chalara fraxinea already present in woods in Norfolk and Suffolk, Britain faces the threat of a "national tragedy" facing one of the best-loved features of its landscape, he said.
Mr Cotterell told the Today programme: "We are very pleased to hear that the ban is going to be announced on Monday. I think the real concern is that geographically, it looks like the disease may have arrived into the wild on the wind."
Asked if the ban would make a difference to the spread of the disease, he said: "It may not. It depends on the extent to which we find the disease in the wild throughout the rest of the country. It has already have been discovered in at least 11 woods in Norfolk and Suffolk."