Why Rats Increased in the UK During the Pandemic

The Research Behind the Claim

Following the first lockdown in March 2020, an MSc student at the University of Derby, Richard Warren, carried out research into the effect on the UK's brown rat population, published through the British Pest Control Association. The study surveyed pest controllers directly and submitted Freedom of Information requests to UK local authorities for rat problem reports covering 2018 to 2022, rather than relying on media reports alone.

What the Data Actually Showed

Over 70% of pest controllers surveyed had experienced an increase in rat-related calls since March 2020, including a 30% rise during spring and summer specifically, a period that would traditionally see the fewest calls of the year. Twelve months on from the first lockdown, pest controllers were still reporting an overall increase rather than a temporary spike. Around 60% felt there had been a genuine increase in the underlying rat population, not just more sightings of the same numbers.

Why It Happened

The research identified several contributing factors: increased domestic waste as people stayed home more, reductions in waste collections and local authority pest control services during lockdown, closures of food establishments removing a major food source, reduced footfall in busy areas emboldening rats to search more openly for food, and increased bird feeding as more people spent time at home or in local parks. Closures of waste sites also increased harbourage in some areas.

An Honest Caveat Worth Including

The research didn't claim lockdown was the sole cause. When pest controllers were asked whether an increase would have happened even without lockdown, opinion was genuinely split, around 38% thought it would have, 37% disagreed, and the remainder were undecided. The honest conclusion is that lockdown accelerated and exposed a pattern rather than single-handedly creating one from nothing.