WAITROSE is to ban sales of high-caffeine energy drinks to children under 16.

The supermarket said customers buying drinks containing more than 150mg of caffeine per litre would be asked to prove they are over 16 years of age from March 5.

The move follows calls by campaigners for a complete ban on the sale of energy drinks to children following findings that their sugar and caffeine content remains high despite reformulation ahead of the soft drinks levy.

Waitrose said its decision was built on existing industry labelling guidelines, which require any soft drink with more than 150mg of caffeine per litre to carry a high-caffeine content warning and state it is not recommended for children.

The British Soft Drinks Association introduced a voluntary code of practice in 2010 stating that high-caffeine soft drinks should not be promoted or marketed to those under 16.

In 2013, Morrisons announced a ban on children under the age of 16 from buying high-caffeine energy drinks in some stores.

Simon Moore, Waitrose director of technical and corporate social responsibility, said: "As a responsible retailer we want to sell these products in line with the labelling guidance.

"These drinks carry advice stating that they are not recommended for children, so we're choosing to proactively act on that guidance, particularly given the widespread concerns which have been raised about these drinks when consumed by under-16s."

Last month, campaign group Action on Sugar (AoS) found that typical serving sizes of energy drinks were larger than other sugar-sweetened drinks at an "excessive" 500ml.

Youngsters in the UK are among the highest consumers of energy drinks in Europe, figures have shown.

Graham MacGregor, professor of cardiovascular medicine and AoS chairman, said described the drinks as "completely inappropriate" for children to consume and said they should be banned for under-16s.

Teachers' union NASUWT welcomed Waitrose's move, saying that one in 10 teachers cited energy drinks as a key cause of poor pupil behaviour in schools.

General secretary Chris Keates said: "Waitrose has taken a positive and responsible step which hopefully not only other supermarkets will follow, but which will also encourage the Government to produce national guidelines on recommended consumption levels of caffeine for children.

"These drinks are readily available legal highs and are leading to children and young people consuming high levels of stimulants, with little known about the long-term health impacts.

"Teachers are left to deal with the effects these stimulants have on pupil behaviour."