The caffeine contained in energy drinks can make people feel wide awake and encourage them to drink more than normal.

Medics say this could also cause problems sleeping and a raised heart rate, although more research is needed.

Charity Drinkaware does not recommend mixing alcohol and energy drinks.

Mixing spirits and liqueurs with energy drinks, such as Red Bull and Monster, has become increasingly popular - in pubs and clubs, and at home.

But recent research suggests that drinking alcohol mixed with high-caffeine energy drinks could be more risky than drinking alcohol on its own, or with a more traditional mixer.

This is because it can make people "wide awake drunk" - a result of the stimulating effects of caffeine and the brain-slowing effects of alcohol.