The government claimed it was powerless to ban imports of infected trees because its “hands were tied” by EU and world trade rules when it was warned in September 2009 that ash dieback disease could have a huge impact on the British countryside, the Guardian has learned.

Head of plant health Roddie Burgess replied to the HTA chair that it had become apparent “fairly recently” that the disease – which the commission understood to be caused by Chalara fraxinea – had a form caused by a different fungus called Hymenoscyphus albidus. This, he said, “was widespread across Europe, including here in Britain.”This fact alone precludes us from initiating an emergency response under the European Union plant health directive and we would also fall foul of our international obligations under the World Trade Organisation.”