Broadcasters, including the BBC, ITV and Sky, and national newspapers will use a new system this summer in an attempt to alert people to the risk of skin cancer.

Instead of warning the public in terms of how long to risk out in the sun, forecasters will rate the strength of the ultra-violet radiation (UVR).

The Solar UV Index system is unveiled on Thursday by forecasters Sian Lloyd, Bill Giles and Francis Wilson.

Old system 'flawed'

Campaigners were concerned that the old method was based on people with average white skin.

The new system, developed by the World Health Organisation, will rate the strength of UVR rays between one and 20.

During the balmiest of UK summers the figure might reach eight, compared with between 10 and 12 in the Mediterranean and up to 18 in northern Australia and parts of Africa.

The HEA wants to show people how to interpret the index depending on their skin colour.

But the HEA points out that the UVR ratings will not relate directly to the factor numbers given on sun cream bottles.

Mini heatwave looming

The new "solar index" is expected to be used for the first time over the Bank Holiday weekend, when a mini heat wave is expected.

The HEA's campaign manager, Christopher New, says: "Armed with the knowledge of the solar index, the public will be able to assess their personal risk of sun damage depending on their natural skin colour.

"For instance, on a sunny summer day in Blackpool the solar UV index could be six.

"For a person with fair skin that burns easily, their risk of skin damage is very high and they would have to think seriously about protecting themselves."

Dr Tony Quinn, a specialist in skin tumours at the Imperial Cancer Research Fund, said: "With the summer coming we are all looking forward to finer weather.

"The introduction of the UV Index this year means that for the first time we will all know much more about how powerful the sun can be."