The UKs Competition and Markets Authority (CMA) has launched an investigation into social media figures over concerns that they are not properly declaring when they have been paid or otherwise rewarded to endorse goods or services.

As part of the investigation, the CMA has written to dozens of celebrities and influencers, some of them household names, to question how they operate and warn them about recent posts that may have failed to follow guidelines.

While no figures have yet been named as part of the investigation, the CMA has said that it will name anyone found to be flouting the rules. The UKs advertising watchdog, the Advertising Standards Authority, has recently intervened in cases featuring Made in Chelsea star Millie Mackintosh, TV presenter AJ Odudu, reality TV star Stephanie Davis and make-up blogger Sheikhbeauty, all of whom failed to make it clear that posts were paid for.

“Social media stars can have a big influence on what their followers do and buy,” said George Lusty, senior director for consumer protection at the CMA. “If people see clothes, cosmetics, a car, or a holiday being plugged by someone they admire, they might be swayed into buying it. So, its really important they are clearly told whether a celebrity is promoting a product because they have bought it themselves, or because they have been paid or thanked in some way by the brand.”

The CMA has asked the public to share their experiences as part of the investigation. The CMAs last investigation of this nature took place in 2016, when the regulator warned dozens of celebrities over their conduct, as well as intermediary firms who were responsible for arranging influencer marketing.