Scientists believe that a boom in biofuels has sparked a massive increase in the need for pollination.

The shortage is particularly acute in Britain which has only a quarter of the honeybees required.

Researchers believe that wild pollinators including bumblebees and hoverflies are making up the shortfall.

The study is published in the journal Plos One.

Food for fuel

The number of honeybees in the UK and elsewhere has been in decline in recent years, with both pesticide use and disease being blamed for losses.