An urgent snake warning has been issued for parts of the UK – here's how it affects London

Time Out

20-05-2025

If you're afraid of snakes, we're afraid it's not good news. An urgent warning about venomous vipers has been issued across the country, with people being urged to keep their eyes peeled for the reptiles.
Before you get hissterical, Britain has been home to one type of venomous snake for years. A new species hasn't arrived, but they have been on the rise in 2025.
What snakes have been spotted?
There's been an increase in sightings of adders (AKA the common European viper) around the UK recently, with the slippery fellas spotted in the south of England, Cornwall and Wales. Sightings have led to local police forces issuing statements warning locals about the animals.
Are they dangerous?
While adders are poisonous, their bites are very rarely lethal to humans. The snakes are also known to be shy and secretive, meaning they rarely approach people.
The Wildlife Trust said: 'The adder is the UK's only venomous snake but its venom is generally of little danger to humans. An adder bite can be painful and cause inflammation, but is really only dangerous to the very young, ill or old.'
The reptiles can also cause harm to dogs, so its best to keep a close eye on furry friends when out for walks. Adders are often found in basking in long grassy areas. They don't often approach pets and are known for hiding or playing dead, but they do bite if startled. The snakes can live up to 15 years and measure up to 80 cm in length.
Where have snakes been sighted in London?
Before Londoners breath a sigh of relief assuming this doesn't affect them, think again. Adders have been identified in the capital.
A project commissioned by English Nature on behalf of the London Biodiversity Partnership's Reptiles Species Action Plan found the snake to be present throughout Greater London.
While the capital's adder population is small, they are here, mainly living in 'woodland edges, grasslands and particularly heathland habitats or brownfield sites where they look for their favoured rodent prey'. So while you're unlikely to spot one slithering in your garden, you could spot one in one of London's parks or natural habitats.