Mutant bed bugs surge in the UK after building resistance to insecticides | News UK

Bedbug infestations are soaring in the UK as the critters are becoming more resistant to the chemicals used to kill them, Metro can reveal.

One London borough alone has had to tackle 40% more bedbug infestations this year, compared to the same period in 2025, data shows.

Pest controllers say they are being flooded with cases and that the parasites are now resistant to most major insecticides.

The cost-of-living crisis has also meant that more people are turning to ineffective DIY treatments that cause infestations to spread out of control.

Bedbugs are small insects that feed on human blood and typically shelter in mattresses, bed frames other cracks or crevices close to where people sleep.

Data gathered by Metro from across the pest industry has revealed a spike in bedbug infestations in 2026.

One London borough – which we have agreed not to name – has already been called in to fight 155 infestations in the first half of this year.

That number is 40% higher than in first six months of 2024, and 50% larger than the same period in 2024.

The 52 infestations the council dealt with in June 2026 is their largest monthly total since before the Covid pandemic.

The bedbug spike is not isolated to London.

James Rhoades, whose company ThermoPest covers the whole of the UK, said he was dealing with double the number of calls out for bedbugs this year.

Chemical sprays using insecticide are one the most common methods used to kill bedbugs.

However there is growing evidence that the insects are becoming increasingly resistant to the toxic treatment.

Rhoades, who employs more offers high-heat treatment rather than chemicals, said his company has recorded a 30% increase in customers turning to them after a failed professional pest control treatment.

He 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.’

Rhoades said he had heard stories from other pest controllers of bedbugs being sprayed with chemicals and ‘just running around like nothing’s happened.’

World-renowned bedbug expert Chow-Yang Lee that insecticide resistance was ‘probably the single most important reason’ infestations have ‘increased dramatically over the year’.

He told Metro: ‘The insecticides used to kill bedbugs increasingly fail to do so, and insecticide resistance is now a leading cause of control failures.’

He said that the pyrethroid class of chemicals were particularly ineffective.

Prof Lee continued: ‘This pushes up infestation numbers in two ways. First, when a treatment doesn’t fully work, the infestation isn’t cleared.

‘Bedbugs survive, keep breeding, and can spread into other rooms or neighboring homes.

‘Second, and more insidiously, 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.’

While bedbug resistance has always been a problem, the challenge is that resistance ‘has deepened, broadened across chemical types and become much harder to overcome’.

London is at the heart of the global resurgence of bed bugs due to the capital’s housing density, international tourism and large rental market.

Since the return of worldwide travel after the Covid pandemic, some London boroughs have faced more than double the number of bedbug infestations, data provided to Metro shows.

One local authority had only 84 infestations in 2021, but as many as 441 in 2023.

Dr Matthew Davies, an advisor to the Greater London Pest Liaison Group, told Metro that this rise in infestations has continued into 2026.

The expert, who is Head of the Technical Department at Killgerm Chemicals blamed the problem in part on a drop in insecticides on the market, making it harder to tackle resistance.

Dr Davies also stressed that resistance is not a ‘doomsday scenario where there are no available options’.

Instead the key route to success in tackling bedbugs is an ‘integrated’ treatment solution where different strategies are used at once.

He explained that alongside chemicals ‘this includes steam treatments, heat treatments, and monitoring for problems with lures.’

There are also fears that the cost of living crisis is pushing more families to swerve professional bed bug treatments.

Many are then turning to DIY methods which can often make the problem worse.

Prof Lee said people are ‘fall[ing] back on cheaper sprays, including shop-bought foggers and aerosols that barely work.

‘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.

‘In other words, over-relying on insecticides that no longer fully work is actively making the resistance problem worse.’

Get in touch with our news team by emailing us at webnews@metro.co.uk.

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