Seven brands of coconut water sold in the UK contain undeclared sugar which is not mentioned on packs, an investigation has found.

The National Food Crime Unit has uncovered hidden sugar in the drink, which is considered a healthy alternative to fizzy drinks and other sugary beverages.

It found added sugar in 60 per cent of samples tested according to the Grocer magazine.

The worst offenders were brands including Chi, Foco, Go Coco, Tropical Sun, Suncrest, Yaco and Pearl Royal.

As a result the authority removed 400 tonnes of coconut water from the market.

The Food Standards Agency said twelve samples of coconut water were analysed, ten of which were deemed to be unsatisfactory.

Seven samples did not meet required standards due to the addition of sugar derived from an external source and/or water; where the inclusion of starch-derived sugar and sugar from plants like sugar cane or maize was noted.