A breeding colony of invasive tropical mosquitoes capable of transmitting dengue and Zika has been identified in east London, marking the first recorded instance of the species reproducing on British soil.

The UK Health Security Agency (UKHSA) confirmed it found adult Aedes aegypti mosquitoes alongside their larvae in a residential area of the capital. Specialist eradication teams have been dispatched to destroy the colony before the insects can spread or establish a permanent foothold.

While individual Aedes aegypti specimens have previously turned up in Britain, a reproducing population has never been recorded here until now. The insects are ordinarily found across Africa and Asia, and historically the UK's cooler climate has prevented them from surviving.

The colony was identified after a resident reported the insects through an online mosquito submission website run by the UKHSA. The exact location has not been publicly disclosed, though photographs show at least one of the properties involved is a well-maintained Victorian house in a middle-class neighbourhood.

The find comes after the UK experienced its provisionally hottest summer on record, creating conditions far more hospitable to tropical pests. Dr Jolyon Medlock, head of medical entomology and zoonoses ecology at the UKHSA, noted: "It is expected that in a warming climate, we will continue to see incursions of invasive mosquitoes and increased reports of them being able to survive in the UK."

Dr César López-Camacho, a researcher at the University of Oxford, explained that elevated temperatures significantly aid the species. "Warmer conditions can accelerate mosquito development, extend the period in which mosquitoes remain active and, critically, increase the rate at which viruses such as dengue or chikungunya replicate within a competent mosquito," he said.

Previous government modelling forecast that Aedes aegypti would be unlikely to gain a foothold in Britain before 2040, but this discovery suggests that projection may need revising. The species has been gradually advancing northward across Europe as continental temperatures rise, establishing populations in southern Europe and leading to dengue cases in Italy, France, and Spain.

If the species were to become permanently established here, illnesses such as dengue fever — which causes high temperatures and intense joint pain, and can prove fatal for young children and the elderly — could eventually become commonplace across southern England.

The wider threat of mosquito-borne illness was demonstrated recently in Germany, where authorities reported two fatalities from malaria after six people were bitten by a single mosquito at Frankfurt airport.

For now, however, the UKHSA stresses the immediate risk to the British public remains low, with no evidence that anyone has been infected by the London colony. As Professor Tom Solomon, director of The Pandemic Institute in Liverpool, pointed out: "A mosquito would first have to bite someone carrying a virus and then, after the virus had developed inside it, bite another person. There is no evidence that this has happened."

Neither dengue nor Zika naturally circulates in the UK, although returning travellers can bring infections home, with 137 dengue cases recorded in the first half of 2026 among British travellers returning from regions including Southeast Asia and South America. Dr Medlock has urged residents to clear standing water from buckets, plant pots, paddling pools, and outdoor containers, and to send photos or specimens to the UKHSA's mosquito watch scheme.

I'll be tracking how the eradication effort in east London progresses — check back for updates as health officials monitor the area.