U.K. anti-vaxxers are flocking to social media to complain about a Christmas ad from Tesco, the U.K.'s biggest retailer, because of a scene that shows Santa brandishing a so-called "vaccine passport."

The ad, by BBH London, debuted on Saturday night and has already attracted 1,500 complaints to the U.K.'s Advertising Standards Authority (ASA), making it the country's most protested ad of the year so far. Meanwhile, anti-vaxxers on social media are calling for a boycott of the retailer's supermarkets. 

The spot is set to "Don't Stop Me Now" by Queen (which, incidentally, was also chosen as the soundtrack to Lego's holiday ad this year) and centers on a series of people determined to enjoy their Christmas after the lockdowns of last year. In one scene, Santa triumphantly produces his double-vaccination "COVID pass" at the border gates after a news channel reported him to be "threatened with quarantine."

While the scene seems playful, its inclusion is potentially incendiary. Anti-vaxxers and anti-lockdown protesters are vehemently opposed to the idea of so-called "vaccine passports," which are required by the government to enter some public venues in Scotland but not England. 

British Prime Minster Boris Johnson so far has avoided making them a legal requirement, but has threatened to keep them "in reserve" if COVID-19 escalates again. However, business such as theaters and concerts venues are increasingly asking for proof of double vaccination via a government-issued QR code. The pass is also required for most international travel.

Subscribe to Ad Age now for the latest industry news and analysis.

The TV ad immediately provoked complaints on Twitter with one woman posting that she would "never be shopping at Tesco again."

Some posted photographs of their Tesco loyalty cards torn up, and threatened a boycott of the stores. Others, however, praised the ad, and several argued that if anti-vaxxers boycotted Tesco, it would actually make the supermarkets safer.

The ASA must now consider whether to uphold any of the complaints against the ad. “The large majority of complaints assert that the ad is coercive, and encourages medical discrimination based on vaccine status," according to an ASA spokesman.

In response, Tesco has issued the following statement: "We respect everyone's views and we know that Christmas is a hugely important time for many of our customers and, after last year's events, that is truer now than ever. We set out to create a campaign which took a light-hearted view on how the nation is feeling and it has been well-received by colleagues and customers. We are still in the midst of a pandemic and the advert reflects the current rules and regulations regarding international travel."

While its celebratory message is similar to many other U.K. retailers this year, Tesco's is more unusual in that it does at least refer to the ongoing disruption to life due to the pandemic—there's even a playful reference to food shortages, with people improvising with other vegetables when carrots aren't available for their snowman's nose.