"Genetic mutations have produced a new breed of "super rat" with DNA that protects the vermin from standard toxins, according to Professor Robert Smith at the University of Huddersfield.
Ratcatchers in Berkshire and Hampshire were the first to report that their poisons were no longer effective, which experts put down to increased immunity among the pests.
But as the poison-resistant rats continue to spread, tests have revealed that they boast an entirely new strand of DNA that wards off attacks from pesticides.
Swindon in Wiltshire is the latest town to suffer an infestation, with exterminators reporting a 500 per cent increase in the rodents. Many are turning to traps, air rifles and even dogs in an effort to keep the populations under control."
"Britain is reported to have around 80 million rats, a rise of more than 200 per cent since 2007."