Natural environment under secretary Richard Benyon said: "To protect biodiversity we need biosecurity. Without that, pests and diseases threaten biodiversity. Global trade increases risks, while climate change enables pests to spread."
He explained that Defra would work with Kew, the Forestry Commission and the Food & Environment Research Agency on the plan, which was prompted after attacks of killers such as Phytophthora ramorum and oak processionary moth.
Forest Research principal pathologist Joan Webber said the action plan was being finalised after six months of talks with stakeholders and would look at public consultations as well as shortand long-term measures to improve security.
Kew's new 750sq m glazed block includes eight sealed quarantine bays under negative pressure, so if a window breaks, air is sucked into the bay to prevent pests escaping. Designer Unigro included a spotless loading bay with double shutters for airtight fumigation.
Incinerators burn dry plant waste and packaging such as wood, board and binding to prevent contaminated material escaping. All used water is sterilised before going to waste and staff pass through cold zones to shock pests into falling off their clothing.