In 1983, Britain reintroduced a butterfly declared extinct just four years earlier; the large blue has since surged 1,866% and now survives at 33 sites

• A butterfly once declared extinct in Britain is now at the centre of one of the country’s most striking conservation success stories.
• The large blue, which disappeared from Britain in 1979, has been successfully reintroduced and now occurs at 33 sites in south-west England.
• New figures from the UK Butterfly Monitoring Scheme show its recorded abundance has risen by 1,866% since 1983.