Warmer weather is finally here and a lot of people up and down the country will be eagerly packing the sun cream ready for their next holiday abroad - or maybe just a cheeky sunbathe in the garden.

But what many people don’t realise is that there’s a symbol printed on the back of every sun cream bottle.

And ignoring it could mean the difference between getting a nice tan and burning your skin red raw - which has been linked to all sorts of conditions such as skin cancer.

Every single bottle of sun cream, sun tan lotion or sun block has a symbol printed on the back. This symbol usually looks like a tin with the lid slightly ajar, with two letters and a number printed next to it. This is the expected shelf life of the product and how long it will remain safe to use while still protecting you.

For example, a bottle of sun cream which says ‘12M’ on the back mean that it’s only guaranteed to last for 12 months without going off and becoming less effective. Some creams may say 6M, which means it’s safe for six months, but 12M, for 12 months, is the most common.

If you use sun cream older than the amount on the symbol, for example because you pulled out a leftover bottle from last summer, you need to be sure it’s still in date or it might not protect your skin.

Using old sun cream may mean you still burn and put yourself at risk of skin cancer because it won’t block out harmful UV rays as effectively.

The best way to make sure you know how long you have left to use it is to write the date you bought the sun cream in permanent marker on the front of the bottle. That way you can’t be caught out by an old bottle in the back of your cupboard.

The same 12M symbol can be found on various cosmetics, from lipsticks to shampoo, conditioner and moisturiser, so always check the label if you’ve got old bathroom products building up, too.