City rat infestations have surged dramatically across the UK and internationally, driven by a complex interplay of environmental and human factors. John Gladwin’s unsettling experience of discovering rats inside his Croydon home highlights a growing urban crisis: residents increasingly face the harsh realities and health risks posed by flourishing rodent populations in close quarters.

The rise in rat activity is corroborated by pest control professionals and local authority data. Cleankill, a south England pest control company, reports a remarkable 20% increase in rat-related callouts over the past two years, while the British Pest Control Association (BPCA) confirms that more than half of its members have noted rises in rat infestations nationally in recent years. Official figures obtained by the drainage repair firm Drain Detectives reveal more than half a million rat infestations reported to UK councils between 2023 and mid-2025. London alone recorded over 76,000 infestations in this period, with boroughs such as Camden, Islington, and Brent among the worst affected. Other regions, including the North West of England and Scotland, have also faced tens of thousands of infestations, pointing to a nationwide challenge.

Statistics from local authority pest control services underline the scale of the problem. Councils made close to 300,000 visits to homes across the UK for pest-related issues in 2024, with 91% of these addressing rodent problems. The number of rat or mouse-related callouts increased steadily year on year, with some councils like East Suffolk experiencing rises exceeding 300%. Councils spent an estimated £40 million tackling rodent infestations in 2024, underscoring both the financial and social costs involved. However, pest control provision varies widely, with over a quarter of UK councils not offering such services and significant disparities in fees charged to residents for pest eradication.

Experts point to a constellation of contributing factors. These include reduced frequency of rubbish collections, urban development disrupting sewer systems, and a cultural shift towards fast food and disposable packaging, which provide plentiful, accessible food for rats. Added to these is the effect of climate change. Research led by urban rodentologist Dr Bobby Corrigan, including a study published in Science Advances, has shown that rising temperatures correlate strongly with increased rat activity in cities across North America. Notably, cities experiencing greater temperature increases saw more substantial surges in rat populations, with rises as high as 400% in Washington DC and 300% in San Francisco documented over recent years. Warmer winters reduce rat mortality and increase breeding success, allowing populations to explode, as rats do not hibernate and are prolific breeders.

The biology and behaviour of rats further complicate control efforts. Rats’ inability to vomit and their natural caution in trying new foods makes many poisons ineffective. They quickly learn to avoid baits that cause discomfort, and growing genetic resistance to anticoagulant poisons has been documented. Scientists, including Dr Alan Buckle from the University of Reading, acknowledge the difficulty in developing effective, humane poisons. Consequently, alternative approaches, such as oral contraceptives for population control, are being explored.

Municipalities are responding with innovative measures. New York City appointed Kathleen Corradi as a "Rat Tsar" in 2023, charging her with public education and enforcement efforts. Corradi and her team have introduced “rat walks” to educate residents on how human behaviour influences rat presence and have mandated the use of rat-proof bins to cut off food supplies. This strategy aims to reduce the reliance on poison by removing the sustenance that enables rat populations to thrive. Early results suggest such approaches can have an impact when widely implemented.

Returning to Croydon, the local infestation vividly illustrates the scale of the problem when food sources are plentiful and waste management is inadequate. Pest controllers observe rats boldly scavenging from overflowing bins, making eradication extremely challenging without addressing underlying sanitation issues.

As urban populations grow—with the UK’s population projected to reach 72.5 million by 2032, increasingly concentrated in cities—the convergence of dense human living, climate change, and waste management challenges suggests rat infestations may worsen unless coordinated efforts take hold. Dr Corrigan argues that more than poisons or eradication campaigns, “taking care of our city environment” by cutting off food and shelter for rats offers the most humane and effective long-term solution. However, the scale and complexity of the issue mean that without urgent, sustained action, cities worldwide will continue to grapple with what some call “Ratmageddon.”

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Source: Noah Wire Services