Teachers are calling for a ban on the sale of energy drinks to under 16s, because they contain huge amounts of sugar and caffeine and can cause headaches and palpitations.

The NASUWT, one of Britain’s largest teaching unions, described the drinks as ‘readily available legal highs’ which can trigger bad behaviour in the classroom and school yard.

It comes after researchers at Fuse, the Centre for Translational Research in Public Health, based at Teesside University, found that energy drinks were being sold to children for less money than water or fizzy drinks.

Research by Fuse found one in three young people say that they regularly consume energy drinks, which are often sold in promotions of 4 for £1, meaning young people often pool their money and buy the beverages for just 25p.

A single 500ml can of popular brands on the market can contain around 160mg of caffeine, while the European Food Safety Authority recommends an intake of no more than 105mg caffeine per day for an average 11-year-old.