The Times reports a citizens’ army to protect British wildlife and slow the arrival of invasive species like Japanese knotweed is being considered by the government. Such invaders cost the UK economy £1.8 billion a year, according to the Commons environmental audit committee, by damaging biodiversity and transmitting disease. Its members have called for a group of over a million volunteers to be set up to tackle the spread of the harmful species, which also include Himalayan balsam and Australian swamp stonecrop.This would follow the example of New Zealand, which hopes to recruit 150,000 volunteers by 2025 to help monitor and destroy invasive species.