The Soil Association, the UK's biggest organic certifiers, wrote to Mr Benn asking him to prohibit the use of a group of pesticides, called neonicotinoids, which have already been withdrawn in France, Germany and Italy.

The Co-op supermarket has also banned the use of neonicotinoid sprays arguing they damage the neurological and immune system of honey bees.

However, in a letter to the Soil Association this week, Mr Benn said there was no evidence the use of those pesticides caused the decline in bee numbers.

A Defra spokesman said: “The UK has a thorough and robust regulatory system for the approval of pesticides, which many farmers use to produce affordable, high-quality food for consumers, and there is no scientific evidence to support increased restrictions.”

Instead, Defra has invested £4.3 million to investigate the increased prevalence of the varroa mite, the impact of poor weather and the management of disease by some less experienced beekeepers to stem the decline in bee numbers.

Peter Melchett, Soil Association policy director said: “While new funding and new research are welcome, it will not help if the Government ignores existing scientific evidence that has led other countries to ban chemicals known to kill bees.”