Sir Attenborough today announced the construction and planning of 'Butterfly World' - a visitor attraction and conservation scheme.
The dome will be constructed on a 27-acre site near St Albans, Hertfordshire. It will reach across 328 ft across and 56 ft high, with sophisticated sprinkler systems to mimic tropical rainstorms.
The initiative is being launched after figures showed that 76 per cent of British butterfly species have declined in the last 20 years, some of them at a very rapid rate.
Organisers expect the Butterfly World project to be a major tourist attraction north of the M25 and will attract up to one million visitors a year, as well as working to conserve the species.