The UK government is supporting tougher restrictions on the use of neonicotinoids, a controversial pesticide, after findings suggest they pose a greater risk to bees than previously thought.

Environment secretary Michael Gove said further restrictions were justified because of the growing weight of scientific evidence they are harmful to bees and other pollinators, and unless that evidence changes, the government will maintain the heightened restrictions post-Brexit.

Farmers’ groups had argued against a ban on their use in December 2013 because they felt at the time it wasn’t yet backed by scientific evidence and they were seen as important in protecting crops from pests such as cabbage stem flea beetle, which attacks young oilseed rape plants.

But the UK government’s advisory body on pesticides said scientific evidence now suggests the environmental risks posed – particularly to bees and pollinators – are greater than previously understood, supporting the case for further restrictions. Research estimates the value of the UK’s 1,500 species of pollinators to crops at £400m to £680m a year.

“I have set out our vision for a Green Brexit in which environmental standards are not only maintained but enhanced,” said Mr Gove. “I’ve always been clear I will be led by the science on this matter. The weight of evidence now shows the risks neonicotinoids pose to our environment, particularly to the bees and other pollinators which play such a key part in our £100bn food industry, is greater than previously understood. I believe this justifies further restrictions on their use.”

He said he recognised the impact further restrictions will have on farmers and was keen to work with them to explore alternatives. Since 2013, the EU has banned three neonicotinoids – Clothianidin, Imidacloprid and Thiamethoxam – on a number of crops. The European Commission proposes restricting use to plants in glasshouses. Currently, they are banned for oilseed rape, spring cereals and sprays for winter cereals, but can be used to treat sugar beet and as seed treatments for winter cereals. The UK could consider emergency authorisations, but said it would only do so in “exceptional circumstances”.