Last night it emerged that the Forestry Commission was warned in 2009 about the threat of the disease and urged to block imports of ash trees but failed to do so.

The Horticultural Trades Association, which represents growers, visited Denmark in 2009 where its members were “alarmed” by the damage caused by the disease.

The Forestry Commission, however, thought that the disease was caused by a fungus already endemic in Britain, making a ban ineffective. It has since been discovered that the fungus is a new one.