Rat catchers are asking for permission to use stronger poisons to deal with a plague of super rats that have developed resistance to common vermin control methods.
The mutant brown rats, which carry life-threatening diseases, have been emerging from their traditional havens in sewers and ditches and taking refuge in people's homes.
The problem has been made worse by recent wet weather, which has driven hordes of rats from flooded drains.
Some of the worst-hit areas are in the affluent home counties including Berkshire, Hampshire, Oxford and Henley-on-Thames, home to the Royal Regatta.
The Health and Safety Executive has been running a consultation after poison manufacturers applied to use stronger poisons, including brodifacoum which is currently restricted to indoor use, to control the UK's estimated 80 million rat population.
Graham Chapple from Newbury-based Rapid Pest Control told Sky News: "They're super rats in that they've 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 sewers and we've had a lot more calls about people seeing rats in the loft or spotting them during the day, which used to be relatively rare.
"They're just looking for somewhere safe to do what rats do, which is breed prolifically.
"The mutations seem to be spreading reasonably quickly and I know they are having problems in Birmingham, Scotland, Hampshire and other areas.
"It is not so much that brodifacoum is a stronger poison, just that the rats haven't developed resistance to it, so it will be much more effective."
Rats carry diseases that can be passed on to humans, including Weil's disease, which can lead to kidney failure.
Olympic champion Andy Holmes, Sir Steve Redgrave's partner in the 1988 Seoul Games, died from Weil's disease in 2010 after falling ill following a rowing event in Lincolnshire.
Last month a couple in Camden, north London, found their baby girl covered in blood after being bitten by a rat.
In April, grandad Brian Watson told how he battered a "giant rat" to death in Consett, County Durham.
University of Reading researcher Alan Buckle has backed the use of new poisons after finding evidence of rats in Oxfordshire and Berkshire developing resistance to conventional rodenticides.
He told the Daily Telegraph: "Studies show a large part of southern England has rats who have mutated to resist standard poisons.
"Pest controllers are having problems and more potent poisons need to be used carefully and responsibly."
Environmental experts have raised concerns about the danger of brodifacoum - which bleeds the rodents to death - and other strong poisons killing other wildlife, such as barn owls who would eat dead rats, if used outdoors.
The Health and Safety Executive said it had been running a consultation on the issue for the Department of Environment, Food and Rural Affairs.
A spokesman said: "We recognise there may be problems with resistance to some rodenticides in certain areas within the UK and therefore there is a demand for certain products to be used outdoors, which currently are restricted from such use.
"We are considering the current position for dutyholders to be able to use these products.
"To help inform the decision making process HSE has recently conducted a stakeholder engagement initiative and HSE is in the process of reviewing the responses received as a result."