A Unilever advert for Flora butter featuring celebrity chef Gary Rhodes has been banned by advertising watchdogs in the UK for being "misleading".

The advert, which claims people prefer Flora Buttery to rival brand Lurpak, did not have "sufficiently robust evidence" to support the claim, the Advertising Standards Authority (ASA) said.

In the ad, Gary Rhodes carries out a blind taste test on shoppers, asking them to decide which was their favourite spread.

One shopper chooses a crumpet covered in Flora Buttery as her favourite. When asked why by Rhodes, she says: "It seems a bit more creamy".

On-screen text then states: "Out of 200 people tested 48% preferred Flora Buttery, 45% Lurpak Lighter spreadable, 7% had no preference".

Arla Foods, owner of rival brand Lurpak, and 29 viewers challenged whether the ad and the claim was misleading as they believed the "statistical significance" in the consumer preferences demonstrated in the survey was "marginal" and the sample size was "too small" upon which to base the preference claim.

Unilever said the claim 'more people prefer the taste of Flora Buttery' was "not an absolute" claim, but was based on the results of independent research and Gary Rhodes's own experience as Flora Buttery's brand ambassador.

The ASA concluded that the 3% margin of people who preferred Flora Buttery to Lurpak Lighter, was not significant enough to warrant the claim and that 200 participants was not a large enough sample.