NWT Lower Wood in Ashwellthorpe, where ash trees are being investigated for suspected Chalara infection. Pic by Lucy Denman

The government has faced criticism for failing to protect woodlands sooner, after banning ash tree imports to stop the spread of a deadly disease which has taken root in the East Anglian countryside.

The Chalara fraxinea infection was first identified in the UK in February, in recently-planted trees imported from contaminated nurseries in Europe, where the disease has already devastated 90pc of the species in Denmark.

But last week, forestry officials confirmed it had since been found in established woodland in the wider countryside in Norfolk.

Environment minister David Heath was summoned to the House of Commons today to answer questions on the action being taken to control the disease.

He said ash dieback could have “enormous potential consequences” as he confirmed a ban which prevents the import of ash plants, trees and seeds, and restricts the movement of infected trees.

But shadow environment secretary Mary Creagh accused the government of being “asleep on the job” for not taking action to protect ash trees at an earlier stage.

Mr Heath said: “We are taking the threat posed by Chalara fraxinea, or ash dieback, extremely seriously.

“On discovering Chalara in the UK, plant health authorities took immediate action to rapidly assess ash trees for signs of infection at over 1,000 sites where ash plants from Europe had been grown or planted in the last five years. This has resulted in the destruction of 100,000 trees.”

Steve Scott, area director for the Forestry Commission in the East of England, said a “relatively small number” of the 100,000 trees destroyed so far had been planted in Norfolk and Suffolk.

He said: “Before it (Chalara) was found in the wider environment, we were concentrating on following these imported trees through the chain, and the process then was to pull them up and burn them There were one or two sites in Norfolk which had trees from infected nurseries, and a couple more in Suffolk. We are talking about very young planted trees that are easy to pull up and destroy.”

During the Commons debate Ms Creagh welcomed the import ban, but asked why it had taken so long to implement.

“Ash dieback was found last February in a Buckinghamshire nursery,” she said. “Why did ministers sit back, cross their fingers and wait until the disease was found in the wild in June?”

Mr Heath said a voluntary moratorium had been imposed before the ban, which meant no commercial imports had taken place – but he could not guarantee “that no-one brought a little ash sapling back in the boot of their car”.

The discovery of the disease in mature woods has increased fears that one of the country’s most common native trees faces the same fate as the elm, which was devastated by Dutch elm disease in the 1970s.

Mr Heath said the cases in the wild in East Anglia were likely to have been as a result of spores carried on the wind from the continent.

Infected and suspected Chalara sites, including the Norfolk Wildlife Trust’s Lower Wood at Ashwellthorpe, remain open – but visitors are being asked to clean footwear to avoid spreading the disease any further.

The University of East Anglia has launched an “ashtag’’ smartphone application which allows anybody to send a photo of diseased leaves, shoots or bark to plant pathologists who can identify whether the tree is infected.

The app uses geo-tagging software to give a precise location of trees, allowing experts to build up a picture of where the infection is found. People without smartphones can upload images at the website: www.ashtag.org.