Mars UK has faced criticism from the Advertising Standards Authority (ASA) for "misleading" consumers with its Maltesers advert.

The advertising watchdog said the advert, which claimed each chocolate was "less than 11 calories each", suggested they were a "low-energy product".

This claim can only be used to describe products with 40 calories per 100g or less. Maltesers contain 505 calories per 100g.

The ASA also challenged whether the claim "the lighter way to enjoy chocolate" misleadingly suggests Maltesers were lower in energy than other similar products.

The TV ad shows two men and two women sitting on a sofa. One of the woman offers the Maltesers to her friend, saying: "Less than 11 calories each." The other woman replies: "Yeah?  That's not very naughty".

Mars said the claim was not a low energy nutrition claim, however, the ASA concluded that the words "less than" gave the misleading impression that a Malteser was low in energy.

"Following a review by the ASA, future adverts for Maltesers will not indicate that the product contains 'less than 11 calories'," a spokesperson for Mars UK said. "It is true that Maltesers contain less than 11 calories per 2.1 gram sweet. This phrase was intended as a statement of fact on the number of calories in each Malteser rather than to suggest that the product is 'low energy'.

"However, in accordance with the ASA's decision, we will remove this statement from future adverts. The Maltesers advertising campaign will continue as planned, including brand new TV adverts airing in November."