Children should not be given fizzy drinks because they contain dangerous amounts of sugar, UN health chiefs said yesterday.

They also warned adults should halve their average intake to six teaspoons a day to avoid obesity, heart disease and other serious illnesses.

The guideline amount has been slashed dramatically amid fears that sugar poses the same threat to health as tobacco.

Experts blame it for millions of premature deaths across the world every year.

Graham MacGregor, a London cardiologist and health campaigner, said: ‘Added sugar is a completely unnecessary part of our diets, contributing to obesity, type II diabetes and tooth decay.

‘We have known about the health risks of sugar for years and yet nothing substantial has been done.

The UN’s World Health Organisation said the crisis was being fuelled by hidden sugar in processed food and drink such as yoghurts, sauces, fizzy drinks, juice and smoothies.

Last night it published the draft guidelines urging adults to eat no more than 12 teaspoons of sugar a day and to aim for six.

And it said children should try for less than six teaspoons and avoid cans of fizzy drink such as Coke, which contains seven spoons.

The guidelines will now be discussed by academics and medical experts before a final version is published. But Dr Branca said food and drinks manufacturers should drastically alter their products.