Mosquitoes carrying diseases such as dengue fever and the Zika virus could become common in the UK within 20 years.
Experts have warned the insects could call parts of the UK home as temperatures increase.
The UK Health Security Agency warned temperatures could rise by 4C in the country by 2100.
This could see disease-carrying mosquitoes in the UK by the 2040s and 2050s in the worst-case scenario.
Cases could become common in London
PA
Warmer temperatures in the UK have already seen mosquitoes spread to new parts of Europe in recent years.
The Government report said a “plausible worst-case scenario” could see regular cases of dengue fever by 2060.
Symptoms of dengue fever can vary and they are more serious in some people than others.
Common symptoms include rashes, sickness, fever, headaches and body aches.
In extreme cases, Britons will need hospital care and the disease can be fatal.
Professor of climate change at the University of Reading Prof Nigel Arnell said: “Whilst we clearly hope temperatures won’t get that far, it is prudent to prepare for the worst case when planning health resources, if the consequences of us underestimating the risk are so significant.”
Climate scientist and extreme heat researcher at the University of Graz Dr Chloe Brimicombe added: “This report shares a stark look at a worst-case scenario of how unhealthy the future could become in the UK.
“It is unlikely that 4C will be reached, but we should use this report as a positive reminder of building a net zero future that can have positive impacts on our health, for example reducing air pollution and insulating houses to reduce emissions and overheating.
“It is scary to imagine a world where mosquitoes reach the UK, but it doesn’t have to be, when we have the ambition to act on climate change we can protect ours and future generations health.
Warmer parts of the UK could become home to mosquitoes
PA
“It is important to also say that the physical and mental health of the UK is already impacted by climate change, through things like overheating buildings even affecting newborn babies and repeated flooding causing stress on households. This report is one of many in this space that shows we need policy change and infrastructure investment to support our communities.”
A surveillance system is already in place to catch invasive mosquitoes, with a network of traps placed at UK borders.
This comes as cases of the illness were found in Europe over the summer months.
A warning was shared for those travelling to Paris after dengue-carrying tiger mosquitoes pushed through the city.
Cases were also found in other parts of France this summer including the French Antilles, Martinique and Guadeloupe.