The UK's Advertising Standards Agency has backed a television advertisement for KFC Zinger Crunch Salad despite 1,671 complaints, reported to be a record.

The commercial, by Yum! Restaurants for KFC Zinger Crunch Salad featured three women working in a call centre, the agency said. They literally sang the praises of the salad but, as their mouths were full, it was not possible to understand them. Subtitles explained what they were singing. At the end of the advertisement one of the women answered the phone singing "Hello, emergency helpline."

According to 1,671 viewers said the advertisement encouraged bad manners amongst children, making it appear funny to speak/sing with a mouth full of food. Many of the viewers said they were trying to teach their children good table manners and the commercial had undermined their efforts. 41 said their children had copied it.

Nearly all said that they had found the commercial unpleasant to watch. 63 of the viewers said that it was encouraging dangerous behaviour as there was a real risk of choking. 108 also believed that the advertisement presented the emergency services call centres, or call centres generally, in a bad light. 27 viewers thought the commercial was mocking people with either speech impediments or hearing difficulties. 12 other viewers believed that the commercial encouraged over eating.

The complaints were not upheld. "We understood that most parents and guardians tried to teach children good table manners, and the concern of some who thought this advertisement would undermine their efforts," the agency said. "As teaching good table manners is an ongoing process needing frequent reminders at meal times, we did not agree that the advertisement would have a detrimental effect. Once taught good table manners, children would be unlikely to adversely change their behaviour simply by watching this commercial."

"We appreciated that some viewers found poor eating habits unpleasant to watch. In this case, care was taken to avoid the more unsavoury sight of food in the women's mouths," it said. "While the intention was clear, they were shown simply speaking with bulging cheeks."

"The dangers of choking on food are well known, and not just confined to talking while eating," it said. "Children are taught to eat slowly and chew their food to help avoid such accidents. We did not consider, for the same reasons as explained above, that this advertisement would undermine that advice."

The agency did not agree with the complaint that the advertisement showed the emergency services in a bad light. The commercial took place in a call centre. One of the women answered the phone with "Hello, emergency helpline." "There was no suggestion that the call centre was for one of the emergency services," the authority said. "It could have been for any product or service. We did not consider that viewers would take the advertisement's punchline seriously, or that it implied that staff in call centres were unprofessional."

It did not accept the idea that it mocked people with speech impediments either. "It was clear from the commercial that the reason the women could not be understood was because they were speaking with full mouths," it said. "We did not believe that viewers generally would interpret this as mocking those with speech impediments or those who were hard of hearing."

And it would not encourage overeating. "The women were not seen overeating, just talking with full mouths," it said. "We did not consider that the advertisement would encourage over eating."