Brits are being warned that false widow spiders are invading UK homes following a blistering heatwave. Searches for the species have soared by 5,000% this week, while NHS figures reveal hospital admissions linked to spider bites have more than doubled over the past decade.
Heatwave Drives Spiders Indoors
After Britain endured one of its hottest spells of the year, with two consecutive days in May breaking temperature records, the sudden cool-down is now driving a wave of false widow spider sightings across the UK. Oxford University ecologist Clive Hambler, who has described the noble false widow as 'the most dangerous spider currently breeding in Britain', warned: 'The days when you could just treat spiders as benign in Britain are over.'
NHS figures obtained through a Freedom of Information request earlier this year revealed that 100 people required hospital treatment following spider bites in 2025, which is double the 47 cases recorded a decade ago. Experts say the spike in sightings is due to prolonged heatwaves that accelerate breeding in outdoor habitats. When the temperature suddenly drops, booming spider populations begin forcing their way indoors, squeezing through gaps around window frames, door seals and air bricks in search of warmth.
Expert Advice on Prevention
Garden expert Luke Newnes at Hillarys said: 'A sustained hot spell is good news for false widows - warm conditions speed up breeding and push population numbers higher than normal. The cool-down afterwards is what sends them inside. They are not aggressive and they are not hunting people out, but they will move through any gap they can find in a door threshold or window seal. The entry points are the thing to focus on, and most UK homes have not had those checked in years.'
How to Stop False Widow Spiders Getting in the Home
- Check and reseal window and door frames: Exterior-grade silicone shrinks and cracks over time. Any gap you can press a fingernail into is wide enough for a false widow. A tube costs around £5 and takes 20 minutes to apply.
- Replace worn threshold seals and draught brushes: The gap at the base of a back or side door is one of the most overlooked entry points. Brush strips cost under £10 from most hardware stores.
- Cut back ivy and climbing plants touching the house: Cutting back by 30cm from the wall removes the bridge between garden populations and gaps around frames, without harming the plant.
