Britain's Chief Medical Officer has outlined measures to keep people safe in unusually hot weather.
In severe heat the human body can overheat and dehydrate, leading to heat exhaustion or heatstroke. Heatstroke can result in irreversible damage to the body, including the brain, or death.
The plan from Sir Liam Donaldson identifies four levels of alert and action for the NHS and other public bodies. High temperatures would trigger the 'Heat-Health watch' system that will operate from 1 June to 15 September.
Actions range from giving advice on how to keep cool at level one, through to level four where heat can pose a serious threat to health, and the emergency services may be involved.
The contingency plan follows widespread problems across Northwest Europe last summer and predicted climate change. There were 2,000 'excess deaths' in England during the August heatwave last year.
Temperatures across much of the UK over the next few days are forecast to reach 28 to 30 Degrees Centigrade. Officials are preparing for early use of the new service.
A leaflet called 'Heatwave - a guide to looking after yourself' will be distributed nationally. It includes the following advice: