Bedbug infestations are soaring across the UK as the insects develop resistance to the chemicals used to kill them, according to data obtained by Metro. One London borough has dealt with 155 infestations in the first half of 2026, a 40% increase compared to the same period in 2025 and 50% higher than in 2024. The 52 infestations recorded in June 2026 alone represent the highest monthly total since before the Covid-19 pandemic.
Pest controllers overwhelmed by resistant bedbugs
Pest control companies report being flooded with cases, with evidence that bedbugs are now resistant to most major insecticides, particularly pyrethroid chemicals. James Rhoades, whose company ThermoPest operates nationwide, said he is handling double the number of bedbug callouts this year. His firm, which specialises in heat treatment rather than chemical sprays, has seen a 30% increase in customers seeking help after a failed professional pest control treatment.
Rhoades told Metro: "Year on year, we are seeing more cases where people are coming to us. The data definitely suggests that there is a lot more resistance to chemicals than there ever has been." He added that he has heard reports of bedbugs being sprayed with chemicals and "just running around like nothing's happened."
Insecticide resistance driving infestations
World-renowned bedbug expert Professor Chow-Yang Lee said insecticide resistance is "probably the single most important reason" infestations have "increased dramatically over the year." He explained: "The insecticides used to kill bedbugs increasingly fail to do so, and insecticide resistance is now a leading cause of control failures." The pyrethroid class of chemicals, once a mainstay of bedbug control, is now particularly ineffective.
Professor Lee described a vicious cycle: "When a treatment doesn't fully work, the infestation isn't cleared. Bedbugs survive, keep breeding, and can spread into other rooms or neighbouring homes. Every time a population is hit with a chemical it can withstand, the few weakest bugs die, and the toughest survive to reproduce. Repeat that over many treatments and you're left with a population that's almost entirely resistant."
London at the heart of resurgence
London's housing density, international tourism, and large rental market place the capital at the centre of the global bedbug resurgence. Since international travel resumed after the pandemic, some London boroughs have seen infestations more than double. One local authority reported just 84 infestations in 2021 but 441 in 2023. Dr Matthew Davies, an advisor to the Greater London Pest Liaison Group and Head of the Technical Department at Killgerm Chemicals, confirmed that the rise has continued into 2026.
Integrated approach recommended
Dr Davies attributed part of the problem to a reduction in the number of insecticides available on the market, which makes it harder to tackle resistance. However, he stressed that resistance is not a "doomsday scenario where there are no available options." Instead, he advocates an integrated treatment solution combining multiple strategies: "This includes steam treatments, heat treatments, and monitoring for problems with lures."
Cost-of-living crisis worsens problem
The cost-of-living crisis is pushing more families to avoid professional pest control, opting instead for cheap DIY treatments such as shop-bought foggers and aerosols. Professor Lee warned that these methods often make the problem worse: "Every one of those partial treatments does two unhelpful things: it leaves enough insects alive to keep the infestation going, and it kills only the susceptible individuals, leaving the resistant ones to survive and breed. Over-relying on insecticides that no longer fully work is actively making the resistance problem worse."
