Popular video-sharing app TikTok has apologised after it emerged that children were being pressured into giving money to their favourite influencers. TikTok allows fans to send rewards to their favourite video makers on the app in the form of ‘digital gifts’, which can cost as much as £48.99. These gifts are often exchanged for perks, and in some cases influencers on the platform have been offering their phone numbers to children in return for cash, according to a BBC investigation. One child, aged 12, said that she had sent two £48.99 gifts, known as ‘drama queen’ gifts, to US-based TikTok star Sebastian Moy to show appreciation for his videos. After she had sent the first one, Moy asked her for another and promised his phone number in exchange. When the girl tried to contact him, he never answered. But according to TikTok rules, Moy, who has 3.8 million followers on the app, has not done anything wrong. What is TikTok? TikTok is a video sharing app that lets people post 15 second long recordings of themselves. Popular posts include people lip syncing and dancing. Videomakers with more than 1,000 followers are allowed to broadcast live. It is during these live streams that fans can send digital gifts. These appear as on-screen animations. They can range from 5p to £48.99 in value. TikTok has not confirmed how much of a cut the app takes, but influencers told the BBC that they receive around half of the money gifted to them. Tiktok is the world’s fastest growing social media app and is believed to have been downloaded more than a billion times. It has 500 million regular active users. The company is owned by Chinese firm called Bytedance, which says that most of the app’s fans are aged between 16 and 24. However there have been lots of reports of children below the age of 13 using the app, despite the fact that this is against TikTok’s rules. How much money has been spent? The BBC looked into dozens of different influencers’ live streams over a 10 week period and monitored how the gifts were being used. The investigation found that influencers promised their fans shout-outs in videos, or offered to follow their fans on social media, in return for the money. "Some creators routinely offered personal messaging details and phone numbers in exchange for gifts," the investigation explains. "The BBC also found a group who scoured the app for people giving gifts and then contacted them directly asking for money in exchange for 'likes' and 'follows'." In one case, a TikTok creator promised to talk to a fan on Instagram for a week in return for gifts amounting to £147. Sums of more than £100 have been paid to influencers by children on a number of occasions. One parent found her daughter, 11, had run up a bill of £240 on the app. "I was shocked when I found out what the money was spent on," she said. "I said to my daughter, 'So you don't actually get anything for it?' and she said, 'No.' "Adults should know better. And even other teenagers should know better - that you do not ask children for money." Another TikTok user admitted to the BBC that she felt “exploited” and regretted spending up to £600 on gifts for her favourite influencers. And a man named Rhys said that he had spent nearly £1,000 on the app, likening the feeling of giving the gifts to gambling. He said, “It gets addictive. I really didn't see anything wrong with it at the time but now I don't think it's worth it.” What do influencers think? The Neffati brothers, based in Blackburn, have amassed more than 2.5 million followers on Tiktok with their comedy and dancing videos. The BBC’s investigation revealed that they regularly offer to follow people on social media in return for the £49 gifts. The pair told the BBC that they were just doing the same as other creators on the app, and that the average age of people who sent them money was 30. However, they did admit to feeling guilty when they saw that they had been sent money by children and said that they asked them if their parents knew. What is being done? On Tuesday (2 Jul), the Information Commissioner's Office revealed that it was launching an inquiry into whether TikTok was doing enough to safeguard its youngest users. Information commissioner Elizabeth Denham said, “We are looking at the transparency tools for children, at the messaging system, which is completely open, at the kind of videos that are collected and shared by children online. “We do have an active investigation into TikTok right now, so watch this space.” And Tiktok owner Bytedance told the BBC that it was investigating digital gifting. In a statement it said, “"We do not tolerate behaviours that are deceptive in nature and we are sorry to hear some of the users' experiences. "We recognise there is always room for improvements in terms of making guidelines and information more accessible, clear and easy-to-understand for all users. "We value your feedback and will further strengthen our policies and product features."