Rat repellent methods from medieval times to the present day
Rat infestations have always been a problem in UK houses and businesses. It is widely believed that the rodents carried the fleas which caused the spread of the 14th century plague.
Medieval households had various methods of Rat extermination and a healthy supply of cats was often used to keep numbers down.
Small planks of wood propped up on sticks were used as an early form of trap and powdered aconite was also placed in rats' drinking holes as a rat poison but evidently many methods proved futile.
Just as many varied methods of home pest control exist today and choosing the most effective one can be confusing.
Exclusion is one theory and households may try to close holes where they believe rats could enter.
But the rodents can gnaw their way through openings measuring more than 1.3 cm wide and it is not always possible for humans to access such spaces.
Traps that are more advanced than the medieval methods have been known to catch rats, but the rodents must already be inside properties in order to get this far.
Victor rat traps are one of the earliest forms of spring-loaded traps that are designed to break a rat's neck or spine. However many believe such methods to be inhumane and the task of emptying such devices is an unpleasant one.
Poison can be used to repel rats rather than directly killing and according to Animal Science, anticoagulants such as warfarin were used since the 1940s as an extermination method.
But rats began to become immune to the drug in the late '50s, so alternative methods have again been trialled.
Electromagnetic eradication offers a clean, humane, simple way of repelling rodents from houses and businesses.
There are no chemicals involved and the Green Shield electromagnetic device can be plugged into any electric socket.
A pulsating magnetic field is omitted which rats may attempt to put up with for a short while but are repelled by the waves created throughout the building.
It is estimated that 60 million rats inhabit the UK - one for every person.
In May the Guardian reported that the population was growing rapidly and that urgent talks were underway in a bid to halt the rise.