Teenagers off on their first holidays in the sun without their parents are the targets of government-funded health warnings on the dangers of skin cancer.

Young people, who are constantly warned against unprotected sex and excessive drinking, will be advised that they need proper sun protection.

Cancer Research UK, which heads the Sunsmart campaign, says that almost three-quarters of teenagers may increase their skin cancer risk in the search for a suntan.

Seventy per cent of the 16 to 24-year-olds who were questioned in a poll of 1,800 people wanted to get a tan on holiday despite warnings of overexposure. Campaigners say young women are the most likely to want to be brown, and more prone to using a low-factor sunscreen.

The teenagers will be told to stay in the shade between 11am and 3pm, cover up with a T-shirt, wide-brimmed hat and sunglasses and use a sunscreen of factor 15 or above. Mothers of very young children will be the other main sector of the public to receive advice on how to protect their offspring from burning.

Sunburn in childhood can double the risk of melan oma, the most deadly form of skin cancer in later life.

Cases of melanoma have increased by 24% in five years. Almost 7,000 people a year are now diagnosed with the condition.

Charlotte Proby, a dermatologist with Cruk, said: "Many teenagers have grown up with an obsession about getting a tan on holiday. But young skin is very vulnerable to radiation. Unless young people learn to protect themselves properly in the sun, we could be heading for a skin cancer time bomb."