Two giant bird-eating tarantulas with a leg span of up to 10 inches could be on the loose, after babies were found abandoned in a car park.
A member of the public reported seeing two larger spiders leaving the same area.
While the missing tarantulas would not normally be expected to survive in the UK climate, warmer weather could mean that the spiders will stay alive for longer than expected.
The RSPCA is warning members of the public not to handle or approach the suspected parent spiders if spotted, as their hair and teeth can irritate human skin.
Thought to be Brazilian bird-eating spiders, the babies could grow to the size of a dinner plate. The animals were discovered in Somercotes, near Alfreton in Derbyshire, inside pots, some of which had been run over by a vehicle.
It is thought that the spiders were being kept as pets and bred, before the owner abandoned them. Tarantulas live in a warm and humid environment in the wild, and it is unlikely that the young animals would have survived if not found in time.
According to the Wildlife and Countryside Act 1981 it is an offence to release any non-native species into the wild.
The baby spiders have now been taken to a veterinary centre in Nottingham where they will be looked after they are ready to be re-homed. There is a possibility that more eggs found in the pots may still hatch.
Will they hurt me?
While this type of tarantula is one of the largest in the world and is venomous, their venom is not strong and should not affect humans. Being bitten by one might feel similar to a bee or wasp sting.
Locals are concerned that the escaped tarantulas could cause harm to other animals in the area.
Anyone with information about the spiders should contact the RSPCA on 0300 123 8018.