The changes to the regulations, which come into force in 2010, state that the UVA and UVB protection have to be provided in a 1 to 3 ratio.

In practice this means that an SPF 30 product has to provide the equivalent of SPF 10 in UVA protection.

For natural formulators, which rely on mineral filters zinc oxide and titanium dioxide, this can be challenging.

“We had no end of problems trying to reformulate to fit these requirements, but as a market leader we felt it was necessary,” said Graham Hume from Lavera UK.

“Lavera had to reintroduce zinc oxide into its formulations as it provides good UVA protection, but it is a much more expensive ingredient when compared to titanium dioxide,” he added.

SPF 20 not 40

The reformulations are also complicated to explain to consumers, he said, who are used to being able to purchase SPF 40 Lavera products and who can now only get hold of SPF 20.

However, the company has tried to explain to its consumers that the difference in protection in terms of UVB absorption between SPF 20 and 30 is actually only a few percent.