Grey squirrels are set for a population boom after the hot and dry summer produced a bumper crop of nuts and seeds.

Conservation charity the European Squirrel Initiative said 2025 is expected to be a “mast” year for certain species of trees, including oaks, beeches, hazels and chestnuts. This means there will be more winter food to support larger populations of grey squirrels, which are an invasive species and not native to the British Isles.

As a result more cases of tree damage caused by the animals are expected and the endangered native red squirrels, which are around 26% smaller than the invasive greys, will be pushed closer to the brink.

The Royal Forestry Society produced a report estimating that grey squirrel damage in England and Wales could cost at least £1.1billion over the next 40 years.

Charles Dutton of the ESI said: “With an abundant supply of seeds and nuts, we can expect better grey squirrel survival rates through winter, and more resources for breeding, so inevitably populations will increase. When grey squirrels increase in numbers, so we see more damage to trees, particularly by bark stripping.

“That bark-stripping primarily occurs between April and October, at a point when we can expect these bumper populations to be active.”

The ESI hopes to cut the number of grey squirrels through humane and cost-effective solutions, such as spreading female infertility genes through the population.