Conservationists and farm advisers said action is needed on a landscape scale to protect East Anglia’s invertebrates, after scientists in Germany found insect life had plummeted by 75pc in the last 27 years.

The shock discovery indicates that an entire community of flying insects, including butterflies, bees, and moths has been “decimated” since 1989, in 63 nature reserves.

Lead researcher Dr Caspar Hallmann, from Radboud University in The Netherlands, said: “This decrease has long been suspected but has turned out to be more severe than previously thought.”

The dramatic declines occurred regardless of habitat type and could not be explained by weather changes, altered land use and environmental characteristics, scientists said.

Kevin Hart, head of nature reserves for the Norfolk Wildlife Trust, said wildlife in this country is under great pressure too – and the re-drawing of farming and environment policies after Brexit could be an opportunity to find better solutions.

“Having a number of nature reserves is not doing enough, so we have got to go beyond those areas, and start looking at agriculture and a whole step-change in how we do things,” he said. “We’ve got a big opportunity now to put things in place and develop partnerships with landowners, people with special skills and knowledge.”

NFU East Anglia environment adviser Rob Wise said: “It would be useful to have more research into this, including knowing more about the successes that come from creating the sort of habitats that our members are providing in the East of England.

“There has been a huge effort in recent years under agri-environment schemes, and through voluntary measures, to create the most hospitable environment possible for insects to thrive.

“These include restoring or planting more than 30,000km of hedgerows and managing 270,000 hectares of land under the Campaign for the Farmed Environment. Measures include establishing pollen and nectar mixes for bees and other pollinators, beetle banks and planting wildflower meadows.

“This study refers to a long-term decline but we would expect insect numbers to be turning around on the back of the efforts that farmers are making.”

Heidi Smith is business manager for Norfolk FWAG, the farming and wildlife advisory group for Norfolk.

She said: “From a farming perspective even farms that structurally look really good and have been in agri-environment schemes for a long time, and look after their hedges, and have got wildflower meadows – they look good, but they are too ‘clean’. People are doing all the right things, but when you look for the insects, they are not there.

“The grey partridge is a really good indicator of this, because they feed their chicks on insects for the first six weeks of their life, so they are really sensitive to insect numbers.

“It is an enormous problem, because they are the bedrock of the food chain. Agriculture is a part of the problem, but it has a big part to play in the solution.

“But it is not just the farmers. Everywhere is too tidy. If you look at the amount of grass cutting on roadsides and in public areas, there is no tussocky grass any more. Nothing grows more than two inches before the mower comes out.”