Predictions of a hot summer have prompted the Government to issue new advice on how to cope with a heatwave.

The Department of Health published a leaflet - the first to be issued under the new Health Secretary, Patricia Hewitt - with hints on how to handle a heatwave after the Met Office forecast higher than average temperatures in July and August.

The guidelines include wearing loose clothing and drinking plenty of water when temperatures soar.

"This leaflet will help people enjoy the weather and protect them from its potentially fatal effects," Sir Liam Donaldson, the Government's chief medical officer, said.

However, the Met Office tried to dampen down expectations of a long hot summer: "What we are talking about is warmer than average temperatures, not a heatwave," a spokesman said. "The average daily maximum temperature in July and August is 19.5C in the South-west and 22C to 23C in London. That is not scorching."

The long-range forecast is based on average sea temperatures and rainfall over the past 12 months compared with 30-year averages. The spokesman said: "There is a signal on temperature to suggest higher than average levels, but there is no clear signal on rainfall - which is anyway less reliable. The Department of Health wanted something to launch its heatwave guidance on, but it has mutated into something else."

The heatwave of August 2003 showed that very warm weather can be a major killer. In continental Europe an estimated 27,000 died because of the heat. In England official figures suggested around 2,000 excess deaths, 85 per cent of which were among over-75s.

Sir Liam said: "As the experience in 2003 demonstrated, it is particularly important that for those over 75, especially those who live alone or in residential homes, the necessary precautions are taken to avoid serious harm through heat exhaustion and heat-stroke."

Timely preventive measures could reduce excess deaths, he said. The plan would help ensure that the organisations involved in providing health and social care services knew what actions to take if a heatwave arrived.

The plan includes close monitoring of heat-related illnesses reported to GPs and NHS Direct, which would trigger different levels of alert so the NHS and other public bodies can react as temperatures rise.

Paul Cann, director of policy at Help the Aged, said: "Lack of preparedness in the 2003 heatwave across Europe caused a major social, medical and political crisis. While Britain is ahead in its thinking and planning for a heatwave, we would like the Government to invest in the much-needed vital research to ensure these plans would actually work in such an emergency. Increasing numbers of older people in the UK and their vulnerability to hot weather means they are at particular risk in the event of a heatwave. To our shame, the UK has one of the highest rates of 'excess' winter deaths in the European Union and we do not want the same needless suffering to happen throughout our hotter summers too."

How to stay cool

* If you can, stay out of the sun and avoid going out in the hottest part of the day (11am -3pm).

* If you must go out, wear a hat and loose clothes, preferably cotton.

* If you are going to be outside for some time, take plenty of water with you.

* Take cool showers or baths and splash yourself several times a day with cold water.

* Try to eat more cold food, particularly salads and fruit, which contain water.

* Look after older people who are more prone to the effects of heat. Check regularly on ageing relatives and neighbours.