An emergency temporary authorisation has been triggered for sugar beet growers to use a banned pesticide, following forecasts of severe crop virus levels.
Neonicotinoid seed treatments were banned by the EU in 2019 due to their potential impact on the health of bees and pollinators.
In January, for the third year running, Defra confirmed that farmers could use a neonicotinoid named thiamethoxam to protect sugarbeet crops from aphids carrying virus yellows disease - but only if independent modelling predicted an incidence of 63pc or above.
It provoked anger from environmental groups who said the "incredibly brazen" move went against government commitments on pesticide reduction, with "potentially devastating consequences for bees and other vital pollinators."
But the threshold has now been reached, with the Rothamsted virus yellows forecast predicting a national infection level of 67.51pc.
Dan Green is agriculture director at British Sugar, which processes the nation's sugarbeet crops, mainly grown in Norfolk and Suffolk.
"This seed treatment is necessary to protect the UK sugar beet crop and farmer livelihoods from the very high virus yellows forecast for 2023," he said.
"The emergency authorisation contains strict controls to protect wildlife, including restrictions on using the treatment near any flowering crops.
"The British beet industry continues to invest in finding alternative solutions through our Virus Yellows Pathway.
"With NFU Sugar [the National Farmers' Union's sugar board] and the British Beet Research Organisation, we are looking at grower practices, seed breeding programmes and precision breeding through gene editing as a long-term solution to tackle this disease."
Farming minister Mark Spencer said all criteria had been met for the emergency authorisation and, taking into account the strict controls and mitigation measures, "the potential risks of authorisation (including potential risks to bees) are outweighed by the benefits of use in these circumstances."