A study presented at the American Psychological Association conference last month found that higher levels of sexting were accompanied by higher levels of sexual and relationship satisfaction.

London - Eton College has banned a photo-sharing mobile phone app over concerns it is being used to exchange sex texts.

Snapchat has been blocked on the school’s wifi network to prevent pupils sending explicit images to each other.

It is not clear what pupils at the £33 000-a-year all-boys school, the alma mater of David Cameron, have been sharing.

But the app has previously sparked concern over its use by teenage girls for sending explicit pictures of themselves.

Sexting can potentially result in a conviction for child sex abuse if the images involve someone under the age of 18.

Eton head master Tony Little said: ‘It [Snapchat] is blocked from the Eton wireless internet system. Boys can still use it via the 3G network but we hope that blocking it on our network will, at least, make them think twice.’

Snapchat is estimated to be used by up to half of all schoolchildren. It allows users to send images, videos or text – known as ‘Snaps’ – that disappear from the recipient’s phone after a maximum of ten seconds.

Campaigners fear that this has fooled many teenagers into thinking it is safe to send explicit material using the app.

But the time restriction is easily bypassed, as screen grabs can be taken of any picture before it is automatically deleted.