The advent of "mutant rats" resistant to conventional vermin-control methods in Britain has prompted rat catchers to call for the use of stronger poisons.
The rats have been commonly seen in people's homes recently, away from their regular haunts of sewersand ditches, Britain's Sky News reported.
Recent wet weather has driven these rats from drains, exacerbating the problem.
Someof the most-affected areas are in affluent home counties such as Berkshire, Hampshire, Oxfordand Henley-on-Thames.
As a result, the Health and Safety Executive is running a consultation after poison manufacturers applied to use stronger poisons, including brodifacoum, which is currently restricted to indoor use, to control the growing rat population in the country.
Mr Graham Chapple from Rapid Pest Control told Sky News: "They're super rats in that they have genetically mutated and developed resistance to the poisons we currently use."
"The recent wet weather and flooding we've had has seen them pushed out of the sewersand we've had a lot more calls about people seeing rats in the loft or spotting them during the day, which used to berelatively rare."
Rats carry life-threatening diseases that can be spread to humans.
These include Weil's disease, which can cause kidney failure.
Last month, aLondon couple found their baby girl covered in blood after she was bitten by a rat.