A number of brands have suspended their advertising campaigns on YouTube, after reports about the way the site's system for tackling predatory comments on children's videos.

Mars, Cadbury, Adidas, Deutsche Bank and Lidl are the brands named by the Guardian in its report on the controversy, which is not related to the recent furoré over disturbing videos being watched by children on YouTube.

Instead, the focus now is on how YouTube deals with explicit comments being posted under videos uploaded by children, with a BBC investigation claiming that YouTube's tool for reporting such comments was flawed. It suggested that there could be tens of thousands of accounts posting in this way.

The comments from the brands in the Guardian's piece will make sobering reading for YouTube. "We are shocked and appalled to see that our adverts have appeared alongside such exploitative and inappropriate content," said Mars' spokesperson.

"We have taken the decision to immediately suspend all our online advertising on YouTube and Google globally. Until we have confidence that appropriate safeguards are in place, we will not advertise on YouTube and Google.

"Whilst we investigate this matter we have suspended all advertising on the channel until we have clarity from YouTube on how this situation occurred and are satisfied that an acceptable solution has been put in place," added the spokesperson for Cadbury.

YouTube had already announced a number of child-protection measures last week after the first controversy about video content broke. Among the changes was a promise to block "inappropriate" comments on videos featuring children.

"We have historically used a combination of automated systems and human flagging and review to remove inappropriate sexual or predatory comments on videos featuring minors," explained the company at the time.

"Comments of this nature are abhorrent and we work with NCMEC to report illegal behavior to law enforcement. Starting this week we will begin taking an even more aggressive stance by turning off all comments on videos of minors where we see these types of comments."