The Advertising Standards Authority has supported a claim by Costa Coffee that "seven out of ten coffee lovers prefer Costa" to Starbucks.

Starbucks complained to the ASA about Costa ads which, among others, carried the headline "In head-to-head taste tests, 7 out of 10 coffee lovers preferred Costa cappuccino to Starbucks".

While the claim was based on a blind taste test between Costa, Starbucks and Caffe Nero drinks, Starbucks claimed that the ad implied coffee lovers preferred all Costa products to Starbucks, rather than just cappuccino. Starbucks also questioned whether the small print on the ads was sufficiently legible.

However the ASA ruled in favour of Costa on every count. Previously Ofcom disallowed a similar advert run by Costa on a number of radio shows on the grounds that the claim that seven out of 10 preferred Costa had not been qualified.

However the latest ads were permitted as Costa explained how it had come to the conclusion that seven out of 10 people preferred its products.

Jim Slater, Marketing Director of Costa, said, "Costa has been totally exonerated. The adjudication is good news but not a surprise.

"The ASA has run an extremely thorough investigation, which has found Starbuck's complaints to be without merit: 7 out of 10 coffee lovers really do prefer Costa cappuccino.

"The credible, independent research conducted in late 2008 found that seven out of ten coffee lovers indisputably preferred Costa cappuccino to Starbucks and Caffe Nero when sampled in a blind taste test.

"The campaign played an important part in helping Costa Coffee sales increase by 23.4 per cent, with like-for-like sales increasing 5.5 per cent in 2009/10."

Starbucks however said, "It's puzzling that the ASA has changed its mind since its initial findings in our favour - especially as OFCOM ruled the campaign was misleading as long ago as September.

"However, our coffee is Fairtrade and from the best 3 per cent of the crop and the fact we have a record number of customers says more about it than a paid-for survey based on just 57 people."