Basting yourself on the beach could prove an expensive as well as a dangerous holiday occupation. A recent estimate by the National Radiological Protection Board suggests that adequate sun cream protection would cost the average vacationing family around Pounds 200 a week. Considering the high cost of many brands of sun lotion, this doesn’t seem an overestimate.

9(5col) = A campaign for cheaper sun protection by the Co-operative retail chain this summer has exposed the huge mark-ups made on sun cream by some large retailers. The Co-op is selling all suntan lotions at cost price; it says it is concerned that people are not using adequate sun screens after its own research showed there is still widespread ignorance of the risks.

The top brands all retail for around Pounds 8 to Pounds 9 a bottle, almost double the actual cost. Thus a 200ml bottle of factor 25 Ambre Solaire, the most popular brand in this country, will set you back Pounds 9.89 at Boots and at Sainsbury’s, but costs only Pounds 5.78 at the Co-op. And while the Co-op will sell you 200ml of Piz Buin factor 25 for Pounds 5.97, Boots and Sainsbury’s will charge Pounds 11.49.

Own-label ranges sell for around Pounds 5, but at Pounds 9.29 the Boots Soltan factor 25 200ml bottle is nearly as expensive as Ambre Solaire.

Fortunately, it’s not the cost that counts if you’re looking for safety, according to the Health Education Authority. It says that the most effective ways to protect yourself are cheap: you should cover up with tightly woven clothing, a wide-brimmed hat and sunglasses; head for the shade at midday. As far as sunscreens go, the HEA recommends that everyone should use something with a sun protection factor (SPF) of at least 15 unless they have naturally brown or black skin. Medical opinion suggests that children are safest with an SPF of at least 25.

Cream should also protect against UVA radiation as well as the more harmful UVB.

Sun-lotion manufacturers do not want to be seen as irresponsible companies that are encouraging people to over-expose themselves to harmful rays. They are becoming increasingly involved in campaigns to make the public more aware of the consequences of sunburn. A recent survey by Beiersdorf, which manufactures Nivea, revealed that few parents felt a sunscreen was necessary for protection from British sun, although the risk of developing skin cancer in adulthood is enormously increased by sunburn in infancy.

The makers of Nivea, Ambre Solaire, Uvistat and E45 all now produce education packs aimed at schools, while Ambre Solaire has a “Sun Safety Patrol’’ which will be combing British beaches in the summer holidays.