A TikTok post by influencers The Wave House promoting fashion retailer Pretty Little Thing has been banned after the group failed to clearly mark it as an advert.

The ruling is the first complaint upheld by the Advertising Standards Authority (ASA) against the group of six influencers.

The group was set up by management company Yoke and now boasts 4.1 million TikTok followers of the social media content it creates from a mansion in Essex.

The post, seen in October, featured two men wearing leather jackets and sitting in convertible cars and two women in pink jackets with Pretty Little Thing embroidered on the back.

The next clip showed the women waving a racing flag down to signal the start of a race between the men and the description: “Who do you think won this race? @prettylittlething #grease #fyp”.

A viewer complained that the post was not obviously identifiable as an ad.

Pretty Little Thing confirmed that its contractual agreement with The Wave House said all social media posts must be obviously identifiable as an ad by using the #ad disclosure.

The retailer also confirmed that The Wave House was unable to update the post to include the disclosure and so the whole post was removed.

The Wave House – Eloise Fouladgar, Jimbo H, Kate Elisabeth, Millie T, Carmie Sellitto and Spencer Elmer – said the post was intended as an advertisement in partnership with Pretty Little Thing.

They said the ad was posted in error without the required label and they would have rectified it if they had noticed it themselves.

The ASA said there was nothing in the content of the TikTok post, such as #ad placed upfront, that made it clear to consumers that it was an ad.

The regulator said: “We therefore concluded that the post was not obviously identifiable as a marketing communication and as such breached the code.

“We told Pretty Little Thing and The Wave House to ensure that their future ads were obviously identifiable as marketing communications, and that identifiers such as #ad were clearly and prominently displayed.”