The Scottish Government has come under attack for failing to ban pesticides after a major scientific study concluded that they were harming bees.

Scientists from the publicly-funded Centre for Ecology and Hydrology found strong evidence linking the use of nicotine-based pesticides with “large-scale and long-term” declines in wild bees.

But when asked for the government’s response to the study last week, the Environment Minister Roseanna Cunningham said it was awaiting further research before considering whether to take action.

In line with European Union, there are some restrictions on the use of three of the pesticides, known as neonicotinoids, in Scotland. But potatoes, wheat, barley and oats grown over large areas are still treated with the chemicals, which are designed to paralyse insects by attacking their nervous systems.

According to the Scottish Wildlife Trust, the new study was further confirmation that some neonicotinoid pesticides were causing real harm to wild bees. “If the precautionary principle were being properly applied we would fully halt their use in Scottish agriculture, unless it was proven that there is no danger to wildlife,” said the trust’s head of policy, Dr Maggie Keegan.

“The Scottish Government has repeatedly stated that there is not enough evidence to impose a full ban, but as study after study demonstrating the impact of neonicotinoids is published we have to question exactly how much evidence will be enough.”

Matt Shardlow, chief executive of the insect conservation group, Buglife, argued that neonicotinoids were now well established as a factor in the “appalling” decline in bee populations. The existing restrictions were partial and weren’t precautionary, he said.

He added: “It is disappointing that the Scottish Government is sitting on its hands, while France and Germany have both enacted national bans that go beyond the Europe Union ban.”

The Scottish Government’s position, however, was backed by farmers and pesticide manufacturers. The National Farmers’ Union in Scotland (NFUS) stressed it took the health of pollinators like bees very seriously.

“NFUS notes the recent research but we continue to firmly believe that it would be inappropriate for Scotland to take unilateral action and agree with the Scottish Government’s position on this issue,” said the union’s deputy policy director, Andrew Bauer.

“Decisions on the use and withdrawal of plant protection products are – and should continue to be - taken by the regulators and be based on the best available science and take into account risks, costs and benefits.”

Bayer Crop Science, which makes and sells neonicotinoids, argued that the study was statistical and suggested that intensive modern farming methods were causing “some issues” for bees. “Whether this is due to the use of insecticides is not clear,” said company spokesman, Dr Julian Little.

“A lack of nesting sites and pollen and nectar sources in these areas may also be critical factors. The ban on the use of certain neonicotinoid insecticides on flowering crops has been in place since 2014.”

On behalf of the Scottish Government, Cunningham welcomed the new study. “We consider this an interesting and useful piece of research, and note that the authors acknowledge that many factors are linked to pollinator decline,” she said.

“We await the results from the soon to be published Centre for Ecology and Hydrology large-scale European field trials. These results are expected to address some of the scale and replication challenges of previous field studies, which investigated the potential impact of neonicotinoids on pollinators.”

The results would be fed into the European Food Safety Authority's (EFSA) assessment of all the new research findings on the use of neonicotinoids, the minister added. “EFSA expected to publish a report summarising their findings by the end of January 2017, which we will carefully consider.”