Bees become addicted to pesticides in the same way that humans grow dependent on cigarettes, new research has found.

The more of the nicotine-like chemicals they consume, the more they appear to want, a study has shown.

The findings suggest that the risk of potentially harmful pesticide-contaminated nectar entering bee colonies is higher than was previously thought.

Controversial neonicotinoid pesticides are chemically similar to nicotine, the addictive compound in tobacco.

In 2013 the European Union imposed a partial ban on three widely used neonicotinoids because of evidence that they may be harmful to bees.

The ban has now been extended to cover all crops not grown in greenhouses, despite strong opposition from some groups including the UK's National Farmers' Union, but it could be revoked following Brexit.

In a series of studies, a team of British researchers offered bumblebees a choice of two sugar solutions, one of which was laced with neonicotinoid pesticides.