Pest controllers are warning about the danger of the rapidly expanding rat population in Britain.
Rat catchers say it is important to exterminate before they breed
Wet weather has been blamed by experts for the 1.6m infestations reported across the country in 2006.
Some pest controllers say they have had 30% more business this year, and are urging anyone worried about a rat problem to get in touch right away.
Rats can damage buildings by gnawing through materials. They can also spread disease and illness.
Rats are prolific breeders and can produce 200 offspring a year.
Experts say a number of factors are responsible for the increase. Many blame climate change, in particular the wetter weather.
Peter Crowden, a pest controller in the East Midlands warned: "The rats are moving into city centres where there's a ready made food supply for them from fast food restaurants to rubbish being left about.
"We also experience a lot of fly tipping. That doesn't help and it's great for the rat population."
Disease is another major concern. Hair, droppings and urine can contaminate food and surfaces.
It is estimated between 15 and 30 % of the rat population carries the potentially deadly Weils Disease.
Pest controllers are urging people to keep alert for rats and call the experts in immediately.
Rats like to burrow into walls to make nests. They can run up drainpipes or wall plants to get into roof space.
The creatures can cause serious damage to property by gnawing through materials and chewing through pipes and cables.
The film Ratatouille welcomed animated rats into the kitchen
Peter Crowden said: "If someone has a problem they should get professional help straight away because with the breeding cycles they can soon get established and cause a tremendous amount of damage."
Rats have traditionally been vilified but they have enjoyed a rise in popularity this year with the release of the hit Disney film Ratatouille.
The animated rats turn out to be culinary experts while the rat catcher is cast as the villain.
The film has also led to a surge in the number of pet rats.