In a world where face to face conversations are becoming increasingly rare, it may be tempting to try and soften the blow of a harsh message or a difficult request with a "smiley".

But you might want to think twice before you try and lighten the tone, as the digital image of a smiling face can have the opposite effect to an actual smile for the person on the receiving end, researchers have found.

Emojis, a popular way to replicate non-verbal communication, are used six billion times a day and have been described as the fastest growing language in history.

Now it seems that like so many jokey messages that have gone down like a lead balloon, the sender could simply make themselves seem less competent.

Concluding that "a smiley is not a smile", academics have even warned that peppering an email with emojis could harm your job prospects by making colleagues less likely to share information with you.