Ahead of what’s expected to be a scorcher of a weekend across the country, it’s a good time to restock on sunscreen.

Before heading to the chemist, however, you may want to be aware of new findings that show two brands may not do as they say on the bottle.

Lab tests carried out by the consumer group Which? show a family sunblock costing £28 fails to provide the protection it promises.

The group found Ultrasun Family SPF30, which comes in a 150ml size and sells itself as “perfect for the whole family” (and “especially suitable for children and those with sensitive skin”), did not meet minimum UVA protection levels.

If you want to know the specifics, it scored a 9.1 and then a 9.5 in a retest, when it should be 10 or more.

Of the 15 brands tested by Which?, Ultrasun was joined by one other in earning its “Don’t Buy” label – Morrisons Moisturising Sun Spray SPF30.

This is sold for £3.75, which gets you 200ml.

It scored 25.7 and 20.7 in UVB/SPF tests – short of the 30 needed to pass.

Cheap solutions

Natalie Hitchins, head of home products and services at Which?, said it was “really concerning” that “widely available sunscreens could be putting families at risk”.

But the tests did also show, she added, that there were plenty of cheap alternatives meeting their standards.

“While shoppers should avoid buying our Don’t Buys, our results prove that there’s no need to splash out to keep you and your loved ones safe in the sun as we’ve found cheap, reliable options”, she said.

These include Lidl’s Cien Sun Protect Spray SPF30 High – costing £3.79 for 200ml – and Aldi’s Lacura Sensitive Sun Lotion SPF50+, priced at £2.99 for 200ml.

How the testing is done

Which? says it uses industry-recognised test methods, which meet British and international standards.

These are carried out at independent labs.

If a product fails on its first test, Which? repeats the test. If it passes on the second attempt, a third test is done. 

If it fails SPF or UVA twice overall, it becomes a Don’t Buy. 

What Ultrasun and Morrisons say

A spokesperson for Ultrasun said it was fully confident in its testing protocols and that its detailed testing processes continued to not only meet, but also surpass, industry standards.

It also said its chosen testing protocol was one of the strictest available.

Morrisons said it was looking closely at the data and working with its supplier to carry out additional independent testing.