Global warming could lead to a return of insect-borne diseases in Britain such as malaria, and increased incidence of skin cancer caused by exposure to the sun, a government report warns today.

With temperatures forecast to rise into the high 30s this summer, scientists fear Britain could be in line for at least one extreme heatwave before 2012. Tick-borne diseases are set to increase, along with the threat of other diseases associated with hotter climates.

The report by a group of scientists for the Department of Health updates earlier warnings that climate change could see heat-related deaths rise to more than 2,800 a year in Britain. Heatstroke claimed the lives of nearly 15,000 people in France in exceptional conditions in 2003, and today's report by the Department of Health warns that could be a taste of things to come in Britain.

The French deaths were caused when temperatures soared to 40C, but some forecasters have warned that Britain could be heading towards such temperatures as a result of the changing climate. Last month was the hottest April on record and plants and wildlife are reacting to the hotter temperatures in a spring which has felt more like summer for many in the south of England.

The report comes as the UN's Intergovernmental Panel on Climate Change (IPCC) prepares to release highly controversial proposals for averting the worst consequences of global warming. They include a major expansion of nuclear power, the use of GM crops to boost biofuel production and reliance on technologies which critics say are unproven. The Department of Health's report says people are learning to live with the consequences of climate change and are taking precautions against skin cancer and other increased risks of disease, but more measures are needed to combat the threats.

One of the main threats could be vector-borne diseases transmitted by mosquitoes or ticks, which are climate-sensitive and can increase or arrive in the country as a result of climate change. There are fears that malaria could re-establish itself unless vigilance is maintained to prevent the malaria-carrying mosquitoes surviving. Experts believe the risk of malaria becoming endemic in Britain is still remote, but more cases could be imported by travellers returning to Britain.