Experts say an “explosion” in the population of false widows is behind the doubling of hospital admissions from spider bites in England in the past decade.
One hundred admissions were a result of “contact with or the toxic effect of spiders” in 2025 compared with 47 in 2015, according to provisional NHS figures obtained under a freedom of information request.
Academics have linked the rise to the increase in the noble false widow spider, a species described as “the most dangerous spider breeding in Britain”, in a 2020 paper by Oxford University ecologist Clive Hambler.
The species, which is known to bite, originates from Madeira and the Canary Islands and was first reported in southern England in 1879.
Mr Hambler, who is a lecturer in biological and human sciences at Hertford College, told PA that “the days when you could just treat spiders as benign in Britain are over”.
“I think if you were going back 50 years, then there would have been hardly any consequences from spider bites in Britain,” he said.
“The incidents of severe bites from spiders in Britain will have increased, as this species (false widows) became hugely more abundant in Britain, particularly in the south.”
There were 43 hospital admissions due to spider bites in 2021, and the figure increased to 95 the following year, the NHS figures show. In both 2023 and 2024, there were 91 admissions.
Mr Hambler said that people are coming into contact with false widow spiders much more often than they realise, adding that he has seen the species in the gardens of Buckingham Palace.
He explained that the venom in the bites can cause pain and itching, but the more serious toxic effects are due to the bacteria carried by the spider, which he said can potentially lead to “amputation, sepsis and death”.
The academic said the species is “much more willing to bite than many people are willing to admit” and that he suspects that many people per day are being bitten.
Mr Hambler said the public should be more aware of the risks that false widows pose without being alarmed.
He told PA: “I think spiders are wonderful things and they’re very important in ecosystems, but you now need to treat spiders in Britain as you might in many other parts of the world – as something to be very respectful of.
“I mean, it’s a balance because people will say ‘oh you’ll cause arachnophobia’, but I don’t think many people are going to die of arachnophobia in Britain but they will die from this thing.”
Mr Hambler said there are a number of reasons why the hospital admissions might have increased in the past 10 years, including the fact that medics are becoming more alert to the fact of spider bites and there are more people in Britain.
The figures obtained by PA reveal that of the 100 admissions in 2025, 73 of these were through the A&E department. This compares to 38 of the 47 in 2015.
Dr Michel Dugon, a zoologist specialising in the evolution and development of venom systems at the University of Galway, said the figures obtained by PA are “interesting” but “not surprising”.
He added that the “most obvious” factor that might have caused the rise is the “explosion in the population of noble false widow”.
“We know that those species indeed can actually bite, that they do have a preference to live in and around houses rather than in natural habitats, at least in the UK and Ireland,” he said.
Dr Dugon said that with increased media coverage on false widows and spider bites over the past few years, some people might have come forward believing they have been bitten by the species when it may have been something else.
“Essentially, when you do not see the spider really bite or capture the spider and you say that you haven’t felt any pain, then it’s most likely not a spider,” he added.
“Because a bite by the noble false widow will actually wake you up. The pain is equivalent to a wasp sting or even more than that.”
Dr Dugon said that spiders are “not aggressive animals” and “don’t particularly try to bite”, adding that 100 cases in England is a relatively minor number.
Adam Hart, a professor of science communication at the University of Gloucestershire, said that while false widows have “expanded their range”, there is no strong reason for the public to be concerned about the species.
He told PA: “While they can bite if handled or trapped against the skin, most bites are mild and severe reactions are rare.
“Basic precautions, such as not handling spiders directly, should ensure the chances of being bitten are minuscule.”
PA
