Despite 378 public complaints about Protein World's infamous "Beach Body Ready" ad, the U.K. Advertising Standards Authority has ruled that it is neither irresponsible nor offensive.

The poster, created in-house and showing a very slim woman in a yellow bikini next to the phrase "Are You Beach Body Ready?" was the subject of a public backlash in April, when 60,000 people signed an online petition to have it banned. A graffiti campaign defaced many of the ads, using slogans like, "Each body's ready" and "You are fine as you are," and a "Take back the beach" protest was organized in Hyde Park.

Carling produced a spoof "beer body ready" version, and plus-sized fashion retailer Simply Be created posters declaring "Every body is beach body ready," while the term "beach body ready" became part of daily conversation in the U.K.

Protein World spent $385,000 on the billboards and told Breitbart.com that it had made around $1.5 million in the first four days after the ads appeared.

The brand -- which launched only 18 months ago and was relatively unknown before the posters went up -- stuck to its guns, and was totally unapologetic about its stance.

When Juliette Burton tweeted "I spent life believing I'm not good enough: I signed," with a link to the petition, @ProteinWorld replied, "Why make your insecurities our problem." Another complainer received the reply, "Here is a shoulder for you to cry on," accompanied by a muscle emoji.

Official complaints to the ASA centered on objections to the ad's implication that a body shape that differed from the "idealized" one on the poster was inferior, and the use of a very slender, toned body to advertise a slimming product.

The ASA, however, recognized that "beach body" was a relatively well-understood term and unlikely to cause offence, and that the ad didn't shame women into believing they needed to take a slimming supplement.

The watchdog did, however, ban the ad -- but because of its health and weight-loss claims, which were not the subject of public complaints.

An ASA spokesperson said, "It's not common, but we can and will take action where there is a clear problem under the advertising code. In this instance, we had concerns about the… claims that were appearing in the ad.

The company later brought the ads to the U.S., where they're appearing in Times Square and in the subway system. While there have been online complaints regarding the ads in the U.S., the outrage either didn't reach the same peak or didn't garner the mainstream media attention it did in the U.K.

Protein World had not responded to request for comment at the time of writing.