How to survive being attacked by Britain's most dangerous spider: Venomous false widows are spreading in the UK - and a single bite can trigger agonising flesh-eating infections…

By ANDY BEAVEN, NEWS AND FEATURE WRITER Published: 00:59, 19 July 2026 | Updated: 00:59, 19 July 2026 The idea of Britain being invaded by deadly spiders may sound far-fetched or even alarmist. And for the millions of people in the UK with arachnophobia – a fear of spiders – it’s the stuff of nightmares. Fortunately, these kinds of critters have always been more of a worry for people who live in other countries. But in recent months experts have started warning that, for the first time, spider bites are becoming a real public health problem in the UK. NHS figures published earlier this year show there were 100 hospital admissions in 2025 linked to spider bites – up from 47 in 2015. One cause, they say, is a particular non-native species, which has spread rapidly and is now found across the country – hiding in shoes, bundles of clothes or even seeking out the warmth of people’s beds. With its venomous fangs, the false widow – the size of a £2 coin – can deliver a painful bite, which some biologists believe can potentially lead to anaphylactic shock and severe, even deadly, infections. And since the spiders can enter properties through any tiny gap, there isn’t much that can be done to keep them out. The only precaution for anyone worried about being bitten is to routinely shake out clothing, footwear and bedsheets. Exactly how dangerous these spiders are – and how likely they are to bite humans – is hotly debated by scientists. But despite data suggesting an increase in hospitalisations, plus more frequent reports of severe reactions, the good news is that spider bites in the UK remain relatively rare. So before we head into autumn – when spiders are most likely to be seen scuttling round houses – The Mail on Sunday explores which are harmless, which ones to be wary of, and what to do if you’re unlucky enough to be bitten. Steatoda nobilis, the noble false widow – is capable of delivering a ‘medically significant’ injury Although there are around 650 types of spider in the UK, only a handful are likely to bite humans. And only one – Steatoda nobilis, the noble false widow – is capable of delivering a ‘medically significant’ injury. Having arrived aboard cargo ships in the 19th century, it has spread rapidly in recent years, due to warmer temperatures brought about by climate change. It has a distinctive pointed head, a shiny brown body – like a Malteser chocolate – and distinctive white markings resembling a skull. Clive Hambler, a lecturer in biological and human science at Oxford University’s Hertford College, says: ‘This is the most dangerous spider breeding in Britain – and represents an emerging threat to public health. As recently as the 1980s they were rare even in the south, but since then they’ve spread northwards and are increasingly common everywhere. Their total number has grown significantly and will continue to rise. ‘Spider bites were never an issue in Britain before – which explains the inertia in recognising the spread of false widows as a new paradigm. With people now suffering anaphylaxis, getting sepsis, needing amputations or even dying, spider bites have very much become an issue.’ False widows build messy, tangled webs on rigid surfaces such as traffic lights, railings, window sills, greenhouses, and tree trunks – before hiding in crevices to wait for prey. They also shelter in dark places, including shoes. According to conservation charity Buglife, false widows never attack humans. Spokesman Dr Danniella Sherwood says: ‘People fear these spiders will jump down on to their face and bite. But they’re not dedicated to hurting humans, they’re just crawling around looking for prey. ‘People may be bitten if the spider inadvertently gets pushed against the human’s skin – for example, if a piece of clothing gets thrown on them, then someone puts the clothing on, or if the spider climbs on to a chair or bed then someone sits on it. The spider reacts defensively. It’s terrified. Biting is its only option.’ However, having been bitten repeatedly during decades of research, Mr Hambler doesn’t believe false widows are always innocent victims. He says: ‘It’s often wrong to use human terms such as “aggressive” when describing wildlife – but if there was any species of spider that deserved it, it would be this one. ‘It’s quite prepared to approach much larger organisms than itself – at speed – and then bite. Adam Abrehart, from Bedfordshire, spotted two small fang marks on his right leg – a suspected false widow bite ‘I know from first-hand experience, if you accidentally prod its web it will bite you. ‘There have also been reports of it walking down people’s arms and biting.’ Plumbers, electricians, builders and warehouse workers, he explains, are particularly prone to bites as their jobs often involve poking around in dark or seldom-disturbed places. Many bites also happen when people roll on to the spiders while in bed. He adds: ‘They’re not looking for humans to bite – simply putting themselves in harm’s way by seeking out the warmest place in the house.’ A false widow has fangs which can puncture human skin, leaving a double pin-prick. The danger comes from the venom – which the spider typically injects into captured flies, grasshoppers, or cockroaches, to liquefy the flesh so it can suck up the juices. In humans, neurotoxins in the venom can cause a short-lived condition called steatodism – with intense pain radiating from the bite, swelling, redness, fever and nausea. It has been suggested – although not all scientists agree – that a false widow bite, like the sting of a bee or wasp, can cause anaphylactic shock, a severe and potentially fatal allergic reaction. Some experts have warned that spider bites can also trigger sepsis, a life-threatening response to infection that can cause a dangerous drop in blood pressure, tissue damage and organ failure. One recent case involved a runner whose leg turned black after apparently being bitten. After a 5km race last June, Adam Abrehart, from Bedfordshire, spotted two small fang marks on his right leg – a suspected false widow bite. Although the father-of-three hadn’t noticed being bitten, days later he suddenly felt exhausted and began vomiting. A red patch on his calf turned black. Barely able to walk, the window cleaner hobbled to hospital where doctors found the tissue around the bite had died. Diagnosing the bacterial skin infection cellulitis, they prescribed strong antibiotics. Adam, 34, says: ‘I didn’t realise I’d been bitten until I got home, went in the shower and saw two red dots on my leg. ‘It seemed to be healing, then all of a sudden it got infected: the bite went red. I started being sick. Hours later the bite turned completely black. At the hospital, the doctor said I had cellulitis that had come from the bite.’ In a tragic case, a student died of sepsis after a suspected spider bite left a gaping wound in his back. Harry Bolton was found dead in his flat in Hull days after complaining to a friend that a spider had bitten him. A 2022 inquest heard the 19-year-old and his flatmates had reported a ‘spider infestation’ in their shared student accommodation. Although the father-of-three hadn’t noticed being bitten, days later he suddenly felt exhausted and began vomiting. A red patch on his calf turned black Paramedics noticed a wound the size of a £1 coin on his back. The coroner concluded Harry died from sepsis and added: ‘Had he not been bitten by the invertebrate, possibly a spider, he would not have died at that time.’ False widow spider bites cause infection because their venom contains cytotoxins, which break down tissue and leave ulcers or open sores. And Mr Hambler warns that there is growing evidence that spiders’ fangs also contain antibiotic-resistant superbugs, which make it easier for the creatures to digest their prey but harder for doctors to treat infected bites. He says: ‘We can’t say yet what fraction of bites will lead to these consequences, although it’s still rare. ‘We need to adopt a precautionary principle. Greater awareness of the dangers may make people more arachnophobic, but arachnophobia doesn’t kill people, this spider can.’ Dr Sherwood, however, believes the threat has been over-stated. She says: ‘There have been reports of anaphylactic shock or infections, but the scientific evidence is inconclusive whether these are caused by the spider bite or whether the infection is opportunistic after the spider bite, and being conflated with it.’ And she adds that increased reporting of bites could simply be the result of greater awareness. She says: ‘There may not necessarily be more bites actually happening, but increased anxiety among the public may mean more reports of bites. Some are genuine, but in a large proportion of cases the spiders aren’t definitively seen or taken to the hospital, so can’t be reliably confirmed. ‘There are many other ailments which can be mistaken for spider bites, including insect bites, bacterial infections and skin conditions.’ Aside from the false widow, there are several other species of spider in Britain which can bite a human – although none which cause significant injury. The giant house spider is one of this country’s most common – and fastest. With its 3in (7.5cm) leg-span and dark hairy body, it hides in dark corners on its sheet-like cobweb. But to the alarm of anyone scared of spiders, it can also appear under sofas or in the bath. They become more active in late summer and early autumn as males seek out females. Mr Hambler says: ‘It has strong jaws. Normally it will run away from humans, but if you pick it up and grasp it, it can bite and draw blood. ‘However, there are no known serious medical consequences.’ Others that may also bite if grasped include the woodlouse spider, which is small with a pinkish-grey abdomen and reddish head and legs, and typically live in damp crevices in rotting wood, brick walls and cellars. Another is the garden cross spider, commonly found on large, sticky spiral webs in gardens, and identifiable by a cross of pale spots on its abdomen. Over the centuries, home remedies for deterring spiders have included putting conkers around the house or lines of salt near the doors. More recently people have used pesticide sprays or devices that emit high-frequency soundwaves. But Dr Sherwood dismisses such measures. She says: ‘There are plenty of old wives tales, but they do not work. Nor do spider repellent sprays or devices. It’s impossible to keep spiders out of your house – they are there all year round, which is actually reassuring. If they were really dangerous, we’d all be dropping left, right and centre from spider bites.’ She adds: ‘Spiders keep insect numbers down in our houses and deserve to be celebrated. But anyone who is worried should shake out their shoes – especially outdoor gardening shoes – before putting them on. ‘And if you’re frightened of the spiders in your house, it’s best to safely catch them with a glass and a piece of paper – or get a friend or household member to do it – then relocate them outdoors.’ Depending on the species, a spider bite will either feel no worse than a quick pinch or nip – and may not even be noticed at the time – or else feel as painful as a wasp or bee sting. Like any other minor break in the skin, it can potentially allow bacteria to enter and cause infection. The best advice is not to scratch or squeeze the bite, but instead to wash it with soap and warm water. If any redness, swelling or pain develops – typically within 24 to 48 hours – it may be a sign the bite is infected and medical advice should be sought. Native British species such as the giant house spider, woodlouse spider or garden cross spider can bite if grasped – but their venom is not considered harmful to humans. However the venom of the non-native noble false widow contains a neurotoxin that causes pain. Although the risk of anaphylaxis is currently debated, it is advised to tell a friend or family member you’ve been bitten, so they can check for signs of severe allergic reaction, such as breathing difficulties, throat swelling and dizziness. These would typically appear within minutes, and should be treated as a medical emergency. The venom can also cause steatodism. Symptoms include severe, radiating pain at the bite site which can last for several hours, as well as swelling, redness and intense itching. These can also be accompanied by nausea, headache, lethargy and minor fever, but usually resolves itself within 24 to 72 hours. If the bite starts to itch and swell, consult either a GP or the NHS 111 helpline. If the bite starts swelling severely or throbbing, seek medical advice or head to A&E. Confusion or disorientation, extreme pain or shivering, breathlessness or a feeling of impending doom are all symptoms of sepsis and should be treated as an emergency. It may also be helpful to show the doctor the spider which bit you. Some scientists advise capturing it alive using a glass and piece of paper, while others suggest whacking it with a shoe before taking it as a dead specimen.