TikTok’s pledge to take “immediate action” against child predators has been challenged by a BBC Panorama investigation.

The app says it has a “zero tolerance” policy against grooming behaviours.

But when an account created for the programme – which identified itself as belonging to a 14-year-old girl – reported a male adult for sending sexual messages, TikTok did not ban it.

And it only took such action after Panorama sought an explanation.

The video-sharing platform claimed its moderators did not intervene in the first instance because the child’s account had not made it clear the offending posts had been received via TikTok’s direct messaging (DM) facility.

“We… have a duty to respect the privacy of our users,” it told the BBC, adding that complaints do “not generally trigger a review” of DMs.

However, Panorama’s account had in fact selected and submitted each of the seven chat messages involved via the app’s own reporting tool.

Child safety experts say parents need to be aware of the risks involved with letting their children use TikTok.

“The thing with TikTok is it’s fun, and I think whenever someone is having fun they’re not recognising the dangers,” said Lorin LaFave, founder of the Breck Foundation.

“[Predators] might be looking to groom a child, to exploit them, to get them to do something that could be harmful to them.”

Sex-image message

TikTok does not allow an account to receive or send direct messages if the user registers themselves as being under 16.

But many of its youngest members get round this by lying about their date of birth when they join.

To simulate this, Panorama registered the account with a 16-year-old’s birth date.

But in her profile, it stated the owner was a 14-year-old girl in its biography description.

The team recruited a journalism graduate who creates TikToks for an internet search company.

She is 23, but posed as the 14-year-old, putting her pictures through photo-editing software to make her look younger.

Every day she posted videos, copying popular dances to trending tracks.

These featured hashtags including #schoollife and #schooluniform.

Over the period, the account picked up followers including what appeared to be older men.

One sent a series of DMs in the early hours of the morning asking if the user wanted to see his penis, describing it in explicit terms.

When she responded, the “girl” asked how old he was and he replied, saying he was 34 years old.

She told him she was 14, to which he replied: “Ohhh you are under age sorry.”

He did not send an image or follow-up DMs, but continued to like the account’s videos.

All of his messages were sent to TikTok.

After three days, the man’s account was still active, at which point Panorama contacted the company.

The following day, TikTok banned the man’s account and blocked his smartphone from being able to set up a new one.

A spokesman noted the app offered privacy features to help parents avoid such problems.

“We offer all our users a high level of control over who can see and interact with the content they post,” he said.

“These privacy settings can be set either at account level or on a video-by-video basis.”

TikTok’s moderators also terminated two other men’s accounts without need for follow-up prompts.

In both these cases, the men continued to send the “child” private messages even after she had told them “she” was 14.