The image of cereal bars as a healthy snack is a "myth", according to a study by Which?

The consumer group found all but one of the 30 bars it analyzed were high in sugar, with more than half containing over 30% sugar.

One bar, Nutri-Grain Elevenses, contained nearly four teaspoons - more than in a small can of cola and 20% of the recommended daily allowance.

Other snacks it analysed were found to be high in fat and saturated fat.

The Tracker Roasted Nut bar, for example, was almost a third fat.

Meanwhile, six of the seven cereal bars targeted at children were high in saturated fat, the study found.

And Monster Puffs, a cereal bar marketed to children and described as "great for your lunchbox", contained 43.5% sugar - more than two teaspoons, according to BBC News.