A new breed of 'super rodents ' could be a danger to health, say experts.
In the last 20 years, almost all of the mice and rats in the UK have evolved to be resistant to a common type of poison.
Some 78% of rats and 95% of house mice now have genes that mean they can tolerate poisons known as anticoagulant rodenticides. These normally kill them by preventing blood clotting.
