‘Most dangerous spider’ in Britain behind rise in hospital admissions

An “explosion” in the false widow population is behind the doubling of hospital admissions for spider bites in the UK in the last decade, experts say.

According to provisional NHS figures obtained under a freedom of information request, 100 admissions in 2025 were the result of “contact with or toxic effects of spiders”, compared to 47 in 2015.

Academics have linked this increase to an increase in the royal false widow spider, described as “the most dangerous spider species in Britain” in a 2020 paper by Oxford University ecologist Clive Hambler.

The species known to bite originates from Madeira and the Canary Islands and was first reported in southern England in 1879.

Mr Hambler, a lecturer in biological and human sciences at Hertford College, told PA that “the days when you could treat spiders as benign in the UK are now gone.”

“I think if you went back 50 years, spider bites in Britain would have had virtually no consequences,” he said.

“As this species (false widows) becomes much more common in Britain, particularly in the south, cases of serious bites from spiders will also increase in Britain.”

According to NHS figures, there were 43 hospital admissions for spider bites in 2021, rising to 95 the following year. There were 91 applications in both 2023 and 2024.

Mr Hambler said people came into contact with false widow spiders much more often than previously thought and he had seen the species in the gardens of Buckingham Palace.

He said the venom in bites can cause pain and itching, but more serious toxic effects come from the bacteria the spider carries, which could potentially lead to “amputation, sepsis and death.”

The academic said the species was “willing to bite much more than most people are willing to admit” and suspected a large number of people were being bitten every day.

Mr Hambler said the public needed to be more aware of the risks posed by fake widows without panicking.

He told PA: “I think spiders are wonderful things and very important in ecosystems, but you have to treat spiders in Britain now, as in many parts of the world, as something that needs to be treated with a lot of respect.

“I mean it’s a balance because people will say ‘oh, you’re going to cause arachnophobia’ but I don’t think too many people in Britain will die from arachnophobia but they will die from this thing.”

Mr Hambler said hospital admissions may have increased in the past 10 years for a number of reasons, including medics becoming more vigilant about spider bites and more people being in Britain.

Figures obtained by PA reveal that 73 in 100 admissions in 2025 are through the A&E department. This compares with 38 of 47 cases in 2015.

Dr. Zoologist at the University of Galway, who specializes in the evolution and development of venom systems. Michel Dugon said the figures obtained by PA were “interesting” but “not surprising”.

He added that the “most obvious” factor that could be causing the increase is the “explosion in the population of noble false widows”.

“We know that these species can actually bite, at least in the UK and Ireland, preferring to live in and around homes rather than natural habitats,” he said.

Dr Dugon said that with an increase in media reports about false widows and spider bites over the past few years, some people may have suggested they had been bitten by this species when it could have been something else.

“In fact, if you don’t see the spider actually biting or grabbing the spider and you say you don’t feel any pain, then it’s probably not a spider,” he added.

“Because the noble false widow’s bite really wakes you up. The pain is equal to or even greater than a hornet sting.”

Dr Dugon said the spiders were “not aggressive animals” and “they don’t particularly try to bite”, adding that the 100 cases in the UK were relatively small.

Adam Hart, professor of science communication at the University of Gloucestershire, said although false widows had “expanded their range” there was no strong reason for the public to be concerned about the species.

He told PA: “They can bite if the skin is touched or pinched, but most bites are mild and serious reactions are rare.

“Basic precautions, such as not touching spiders directly, should ensure that the chance of being bitten is very low.”