The sighting in a field in Berwickshire, 100 metres from the English border, has raised hopes that climate change has helped it become the 34th butterfly species to live and breed in Scotland, reports the Guardian.

"Climate change is a double-edged sword but it's an exciting time to be in the Scottish borders," Paul Kirkland of the Butterfly Conservation Scotland said.

More than a quarter of Britain's 59 butterfly species have crossed the border to Scotland.

The white-letter hairstreak normally lives out of sight at the tops of elm trees but was earlier this month spotted in the field.

It suffered its worst year on record in 2016, according to the UK butterfly monitoring survey. Although widespread across England and Wales, it has suffered a 72 per cent decline over the last decade.

Its numbers were down by 96 per cent over the last 40 years.