France will take a radical step towards protecting its dwindling bee population on Saturday by becoming the first country in Europe to ban all five pesticides researchers believe are killing off the insects.

The move to ban the five so-called neonicotinoids has been hailed by beekeepers and environmentalists, but cereal and sugar beet farmers warn it could leave them all but defenceless in protecting valuable crops against other harmful insects.

By enforcing the blanket ban, France is going further than the European Union, which voted to outlaw the use of three neonicotinoids - clothianidin, imidacloprid and thiamethoxam - in crop fields starting on December 19.

France has banned these three, along with thiacloprid and acetamiprid, not only outdoors but in greenhouses too.

Initially opposed, Britain now backs the less comprehensive EU ban due to evidence supporting claims the chemicals contribute to “colony collapse disorder”, a mysterious phenomenon that has seen bee populations plummet by up to 90 per cent in some cases.