House spiders, false widows, and what actually bites in Britain
Hospital admissions for spider bites in England have doubled in a decade. They went from 47 a year to 100. Both of those facts are true, and you have to hold them at the same time to think about this sensibly.
By The Pest GuyLast updated
The short answer
The risk is real, it is small, and it is not the risk you have been told about.
There are around 650 species of spider in the UK. Twelve have been known to bite people. Of those, two or three can give a bite worth calling significant, and the usual symptoms are localised pain and swelling. No spider living in the UK is deadly.
Bites happen when a spider is trapped against skin, most often in clothing or bedding. They are not hunting you and they gain nothing by biting you.
And a house with a lot of spiders in it is telling you something useful: it has a lot of insects in it. That is the whole reason they are there.
The number that gets left out of both arguments
Provisional NHS figures for England record 100 hospital admissions for contact with, or the toxic effect of, spiders in 2025. In 2015 the figure was 47. It has roughly doubled in a decade, and researchers link that to the spread of the noble false widow.
Most pages about spiders will tell you one half of that and not the other. The alarm side reports the doubling. The reassurance side says spiders are harmless and skips it entirely, which is why the reassurance is easy to dismiss.
Both halves are the story. The trend is real and it is going the wrong way. It is also 100 admissions, in a year, in a country of tens of millions of people, in houses that contain spiders in essentially every room. The British Arachnological Society makes the comparison that puts it in proportion: spider bites attract "excessive media reaction when considered against the number of people stung by wasps and bees".
There is a second caution in the same research, and it is one this site has to apply to itself as well. Bites may increasingly be misdiagnosed, because heavy coverage leads people to report a spider bite when they never saw a spider. Nobody, including me, can tell you what bit you from a description.
The false widow, and what it is actually doing here
The noble false widow, Steatoda nobilis, is not a new arrival. It was first recorded in Britain at Torquay in 1879, believed to have come in on cargo from Madeira and the Canary Islands. It sat around in the south west for a century without anyone caring, then built up strongly from the 1980s and has been spreading north since.
It is the most medically significant spider established in Britain, which is a much smaller claim than it sounds. It bites when it is trapped or squashed, typically in clothing. It is not aggressive and it is not deadly.
The part worth actually taking seriously is what happens after a bite rather than the bite itself. The more harmful effects reported are down to bacterial infection rather than the venom. So the sensible response to any spider bite is unglamorous: keep it clean, and see a doctor if it gets worse over the following days or shows signs of infection rather than settling down.
Autumn, and the thing everyone gets wrong about it
Every September the same story runs: spiders are invading houses. They are not. Sightings peak in autumn because the males of many species reach adulthood then and wander about looking for females.
The spiders were already in your house. They have been there since spring, in the cupboard under the stairs and behind the sofa, and you did not see them because they were sitting still in the dark. What changed in September is that the males stopped sitting still.
That reframes the giant house spider crossing your living-room floor in October. It is not an incursion. It is a resident male, near the end of his life, looking for a mate and badly lost.
What actually reduces them
Take away the food. Spiders are in your house because there are insects in your house, and the density of one follows the density of the other. The biggest single lever most people have is outside lighting near doors and windows, which concentrates flying insects exactly where the spiders can reach them.
Then the same proofing that works on everything else: gaps under external doors, holes where pipes and cables come through, unscreened airbricks, gaps around window frames.
What does not work well is spraying, and it is worth being clear why rather than just saying so. A residual spray kills the spiders that walk over it. It does nothing about the insects that made the room worth living in, so the room refills. You have treated the symptom, at the cost of putting insecticide along the skirting of a room you live in.
The conkers, by the way, do nothing. There is no good evidence for it and it has been the same story every autumn for a century.
About this resource
The species counts, the number known to bite, the absence of deadly spiders in the UK and the autumn explanation come from the Natural History Museum. The position on bites, the species that warrant respect, and the wasps-and-bees comparison come from the British Arachnological Society. The admissions figures are provisional NHS data for England, 100 in 2025 against 47 in 2015, as reported in April 2026, along with the researchers' own caution about misdiagnosis.
The honest limits. This page is not medical advice and it is not an identification: I cannot tell you what species is in your bath or what bit you, and the misdiagnosis point above applies to me as much as to anyone. If a bite is getting worse rather than better, that is a question for a doctor and not for a website.
There is deliberately no photograph of a spider on this page. A generated image of a species, shown to someone deciding whether to worry, would be an identification invented by something that has never seen one.
Common questions
Do house spiders bite?
Almost never, and the ones that can are few. There are around 650 spider species in the UK and just 12 have been known to bite people; of those, only two or three give a bite worth calling significant, and the usual symptoms are localised pain and swelling. The British Arachnological Society is clear that bites "are usually accidental and happen only when the spider is trying to defend itself".
Are false widow spiders dangerous?
They are the most medically significant spider established in Britain, and they are still not deadly. There are no killer spiders living in the UK. False widows bite when trapped or squashed, typically in clothing, and the thing worth taking seriously afterwards is infection rather than the venom itself.
Have spider bites really got more common?
Yes, on the recorded figures. Provisional NHS data for England shows 100 hospital admissions for contact with or the toxic effect of spiders in 2025, against 47 in 2015. Both halves of that matter: it has roughly doubled, and it is 100 admissions in a year across England. Researchers link the rise to the spread of the noble false widow, and also caution that heavy media coverage means more people report a spider bite when they never saw a spider.
Why are there suddenly so many spiders in autumn?
They did not move in. Sightings peak in autumn because the males of many species reach adulthood then and walk about looking for females. The spiders were already living in your house, quietly, for months. What changed is that the males started crossing the carpet in the evening.
What actually keeps spiders out?
Less to eat and fewer gaps. A house with a lot of spiders in it is a house with a lot of insects in it, because that is what they are there for. Cutting down the insects, which usually means outside lighting near doors and windows, does more than any spray. Then the ordinary proofing: gaps under doors, around pipe entries and airbricks.
Should I kill them?
Your house, your call, and there is no legal issue with a common house spider. Worth knowing before you decide: they are eating the things you would mind more, and the giant house spiders you find in autumn are usually males with a few weeks left to live regardless. A glass and a piece of card puts one outside in ten seconds.