False Widow Hospitalisations: Why They Rose And What To Do

Expert comment provided by Prof Adam Hart, professor of conservation ecology at the University of Gloucestershire.

In the UK, hospitalisations from false widow spiders reached 100 in 2025.

That’s significantly higher than the figure from a decade before (47 hospitalisations in 2015).

Some have called the false widow spider the UK’s most “dangerous,” though speaking to HuffPost UK, Prof Adam Hart, professor and entomologist, said “serious reactions are rare”.

We asked him why these numbers are rising, how to spot false widow spiders, and what to do if we see them.

False widows are so called because they look like the more dangerous black widow spiders. They were probably introduced to the UK in the 1800s from the Canary Islands.

But their population has been growing here since the 80s, which the expert told us might be why we’re hearing a lot more about their bite.

“Reports of rising hospitalisations from false widow bites perhaps need a bit of context,” he explained.

“The noble false widow has spread widely across the UK in recent decades, so people are encountering them more often. At the same time, media coverage has raised awareness, meaning more people notice them and are more likely to seek medical advice. That could make the issue seem bigger than it really is.”

Additionally, they stay relatively close to humans: “They tend to live around buildings, in sheds, window frames, and sheltered outdoor spaces.”

That makes contact likelier as their numbers grow.

Though noble false widow spiders do bite, Prof Hart clarified that this is very rare and, in most cases, relatively harmless.

“Most bites, where they happen at all, are mild, causing local pain and swelling similar to a wasp sting. It’s also worth remembering that, often, suspected ‘spider bites’ turn out to be something else, such as skin infections or insect bites”.

“False widows are glossy, dark spiders with a rounded abdomen and long legs, often with pale cream markings on the back,” said Prof Hart.

They are usually 7-14mm in length, and the females are generally bigger than the males.

The Natural History Museum describes the pattern on their bodies as “skull-shaped”.

“If you see one, the best advice is simple: leave it alone. If needed, they can be moved with a glass and card,” Prof Hart told us.

“If someone is bitten, basic first aid is usually enough: clean the area, apply a cold compress, and keep an eye on it. Seek medical advice if symptoms worsen or don’t improve.”

And remember, if you can, that while false widows are “now a familiar part of UK wildlife… they really pose a very low risk to most people.”