Source: Food and Environment Research AgencyCases mapped
Officials from the Department for Environment, Food and Rural Affairs are currently investigating suspected cases across the country. So far, the disease - caused by the fungus chalara fraxinea - has been found at almost 300 locations across the UK.
The University of East Anglia (UEA) has also been mapping further "likely sightings" that have been submitted through a free smartphone app, called Ashtag, which allows users to upload pictures and report suspected cases. Information is then passed on to the Forestry Commission.Wider impact
The loss of Britain's ash population would pose a serious threat to the UK plant and animals that depend upon the trees for their survival.
The species forms a significant proportion of the country's woodland cover and contributes to thousands of miles of hedgerows. The network of Wildlife Trusts says any loss of this crucial habitat would have a dramatic negative impact on the natural environment.
Explore the slideshow below to find out which species the ash tree supports.How ash dieback could threaten Britain's wildlife Continue reading the main story
To report suspected cases of ash dieback disease, contact the Food and Environment Research Agency on 01904 465625 or the Forestry Commission on 0131 314 6414. The Forestry Commission has a pictoral PDF guide to the disease that you can download and print.
You can also submit suspected sightings to the University of East Anglia's Ashtag app.