Alex Chalk is MP for Cheltenham.

For over a decade some social media companies have tried to argue that, unlike mainstream publishers, they should not be held to account for what appears on their platforms.

As mere “facilitators”, not publishers, any attempt to tackle harmful online content is technically unfeasible, they say, and even morally unconscionable.

Baloney. It’s an argument that has started to wear increasingly thin. Many now recognise that it no longer acceptable for companies to close their eyes to the material they host. Instead, with great power comes responsibility. Further, technological innovation has made sifting content more feasible than before.

So, whilst no one is credibly suggesting that all harmful on-line content can be instantly erased, there is a growing consensus that social media companies need to do more to play their proper part. That means doing what they reasonably can – first by being transparent about the extent of the problem, and second by being willing to invest proportionate resources to tackle it.

That’s because harmful online content is not limited to so-called “fake news” or extremist material, serious as they are. Its scope is far wider, not least because a significant number of the platforms’ users are children. And when it comes to children, it’s becoming clear that social media, for all its undoubted benefits, can play an insidious role in undermining adolescent mental health – particularly when it comes to online bullying.

This week is anti-bullying week, an appropriate moment to reflect on how bullying is changing. Although still a feature in the analogue world of course, the rise of social media has given it a new – and more potent – dimension. No longer does the torment stop at the school gates. It continues in the back of the car on the way home from school, at the dinner table, and even in a bedroom at night. There are no longer safe havens.

And whilst there are no doubt other factors at play, it’s unlikely to be a coincidence that teenage anxiety is on the rise. Increasingly studies show a clear correlation (if not yet a scientifically proven causal link) between long periods spent online and incidents of adolescent depression.

My cross-party inquiry into cyberbullying, supported by the excellent charities YoungMinds and The Children’s Society, has asked over 1,000 young people about how they experience social media and what they want to see done about the negative side effects of using it. We’ve heard from anti-bullying advocates and social media companies themselves. Significantly, too, we’ve also heard from child psychologists about the long-term damage that bullying can do to brain development.

The inquiry complements the Government’s excellent work on the Internet Safety Strategy Green Paper, which puts the social media companies on notice of their need to do more and does not rule out legislation if necessary.

I believe that there are a number of things social media companies can do. First, they need to be far more robust in actually enforcing their community guidelines. That means taking swift action not just against a particular offending post, but crucially against the culprit themselves.

That might involve the creation of a system of yellow and red cards so that users can be left in no doubt about the consequences of their behaviour. There could be other sanctions too, ranging from suspension of the comment-making facility to prohibition on uploading photos.

And although supportive online communities also have the potential to be refuges for children, they should not be invoked by the social media giants as an excuse for ignoring the kind of toxic interactions that are making so many young people’s lives a misery.

It’s right to acknowledge that this message is starting to get through. Some of the major social media platforms have come a long way. But progress feels tortuous. As one witness to my inquiry put it, some social media companies are “walking backwards slowly”.

Meanwhile, debates about whether self-regulation works, or has ever worked for social media companies, continue. For the children and young people I spoke to, there was no doubt that progress needs to be accelerated. This anti-bullying week, we as parents and users of platforms, should demand social media companies do more.