Leading article: The butterfly effect

It is good to hear that the Adonis blue and white admiral are doing so well this year. No, they are not failed Eurovision bands that have gone on to better things. They are scarce types of butterfly that have increased markedly in numbers recently, partly as a result of this year's warm, dry spring.

It is a rare piece of good news for insects that have been in freefall in Britain for years, victims of climate change, growing urbanisation, pollution and an unfortunate fashion for turning gardens into clinically clean and pollen-free outside "rooms". The days when boys hared round the countryside, nets in hand, clouds of butterflies rising in their wake, are long gone. Most people in cities would count themselves lucky to see the odd cabbage white these days.

The figures make for sobering reading. About 70 per cent of the country's butterflies are in decline and half are in danger of extinction. There is not a lot that we can do about our often damp and butterfly-hostile springs. But we could do rather more to tackle some of the other factors that have robbed the gardens of Britain of the sight of these thoroughly benign, essential and inspiringly beautiful creatures. Whatever we can do to help our stock of "self-propelled flowers", as one writer once called them, we should.