Influencers were responsible for a quarter of all complaints about online adverts last year amid a crackdown on brand promotions on social media.
The Advertising Standards Authority (ASA) received more than 4,400 complaints last year about 3,670 ads that used social media influencers.
The figure represents more than a quarter of all complaints for online adverts, while overall in 2019 the watchdog resolved almost 35,000 complaints about just under 25,000 ads.
It came as the ASA and Competition and Markets Authority (CMA) launched a clampdown on influencer marketing amid concerns over a lack of transparency about when social media personalities were being paid or receiving freebies in exchange for promoting products.
Influencers are now required to label sponsored posts with #ad and last year a string of stars including singers Rita Ora and Ellie Goulding vowed to be more transparent about their social media activity.
The ASA and fellow trade body the Committee of Advertising Practice (CAP) have also targeted irresponsible health claims promoted on social media.
More than 12,000 irresponsible Instagram posts were removed in one quarter following a crackdown on Botox advertising, while the watchdogs have also fast-tracked action against misleading health claims during the Covid-19 crisis.
In addition, the use of so-called avatar monitoring technology — which uses bots to track children’s exposure to adverts — increased last year as part of the ASA’s efforts to tackle problem ads more proactively.
The bots visited more than 250 websites 196,000 times over the course of the year, allowing roughly 95,000 ads to be reviewed.
“Harnessing innovative technology to tackle misleading or irresponsible ads is playing a big part in helping us deliver more effective regulation for consumers and business,” said ASA chief executive Guy Parker.
“And we have some exciting plans ahead, including investment in data science and machine learning. All of which is enabling us to be more proactive and fleet of foot in delivering our ambition to make UK ads responsible, wherever they appear.”