It's all very well slapping on the sun cream, but the best way to block the sun's harmful rays is to cover up. Now clothing manufacturers are coming to the rescue

This summer, like countless before, many of us will go on holiday to a hot destination and burn, and thereby increase our chances of developing skin cancer.

While people have finally got the message that they should use sunscreens, many are still not aware of their shortcomings. A sun protection factor (SPF) of 15, for example, will only enable you to stay out in the sun 15 times longer without burning if it is applied in the same quantity as the manufacturer did when testing it. Research has shown that most people use considerably less, and are typically getting one-third of the protection they think they are.

One of the best ways of protecting skin against the sun is, of course, to cover up. For those willing to forgo an all-over tan, help is at hand to determine which clothes offer more protection than others.

The British Standards Institution (BSI) has launched a new logo, depicting a blazing sun, which clothing manufacturers will be allowed to put on their products' labels if they reach the correct specifications. They will have to offer a SPF of at least 30, which allows for wear, tear and stretch, all of which can reduce the amount of protection by half. The logo is likely to be available by next year.

David Woolliscroft, general manager of the BSI, said he expected that most major clothing manufacturers will want to be involved.

"We already have a British standard for protective clothing, but this one will be applicable to all the European countries. The big thing about it being European is that many of us take holidays in sunny places in Europe, and you will be able to go into a shop and buy a T-shirt, and know what level of sun protection you are buying. It's likely to be on T-shirts and shorts. We are also expecting it to be used for some winter sports clothes as well. Some younger people often go snowboarding in fairly light-weight clothes."

Those who do not have clothes already labelled with their sun protection factor, and who are looking for something to take away with them on a hot holiday, should hold garments up to the light to see how much they let in, advises Dr Colin Driscoll, who runs the sun radiation group for the National Radiological Protection Board.

While most clothes offer a reasonable amount of protection, the best choice would be something with a tight weave and loosely fitted. People who find they only have loose-weaved garments in their wardrobe should choose those in a dark colour, as the dyes will absorb a large proportion of the UV rays. The dyes in strong coloured clothes (even pink or yellow) will provide adequate absorption. The fibres of pure white clothes usually contain brightening agents which also absorb UV rays, as well as reflect them.

The worst colour to choose is off-white, and very pale colours. "These tend not to have the brightening agents, and the dyes in them are not strong absorbers. They will allow the ultraviolet to come through, as determined by the weave of the fabric," said Dr Driscoll.

Mothers who wisely insist that their children should wear T-shirts on the beach, or at the poolside, should be aware that their tops will loose some protection when wet, as the weight of the water makes the fibres stretch.

Nevertheless, for many experts, clothes remain the first line of defence. "Clothes should be the main means of protection, and I feel that sunscreens ought to be the last element," said Dr Driscoll. He added, however, that sunscreens did have an important role to play. A good quality broadband sunscreen should be used on the parts of the body not normally covered, such as the face, hands, feet, and lower arms and legs. "Wear a hat and seek shade," he also advised.