Ash dieback disease will spread across the UK by around 20 miles a year, infecting most of the country’s 90m ash trees within a decade, the government was told Friday at a crisis meeting with its leading environment advisers.

It is feared many more clusters will be identified in the next year and that spores from the fungus will spread from the east of England and Scotland to eventually cover Britain – in some cases carried on people’s clothes. The spores first found in Britain in March can be spread even by the moving of leaves.Trees are more likely to be affected in forests than if they are isolated.

“There is a tidal wave of pathogens coming in. It is terrifying. We have to have a strategic response. Unless we have better biosecurity in the EU and Europe it will be very difficult to stop them coming in. It is difficult to ban all imports. It has to be done on a risk basis,” said Martin Ward, chief plant health officer at Defra’s Food and Environment Research Agency.