Social media causes “no end of issues” as it is “almost impossible to keep track” of it, the headteacher of Molly Russell’s secondary school has told an inquest.

Sue Maguire told North London Coroner’s Court that Hatch End High School did not “present a stance” that students should not use social media, but said it creates “challenges… we simply didn’t have 10 years ago or 15 years ago”.

She said Molly’s death in November 2017 had come as a “complete and terrible shock”, but she added that the school had warned students about the “dangers of social media for a long time”.

Giving evidence from the witness box on Wednesday, Ms Maguire said: “Our experience of young people is that social media plays a huge, dominant role in their lives and it causes no end of issues.

“But we don’t present a stance that they should not use it – but it presents challenges to schools that we simply didn’t have 10 years ago or 15 years ago.

“There’s a level where I want to say it’s almost impossible to keep track of social media, but we have to try and we have to respond to the information as we receive it.”

Asked by the Russell family’s lawyer, Oliver Sanders KC, whether the school was aware of the suicide and self-harm related content available to students like Molly on sites such as Instagram, Ms Maguire said: “At the time, we were shocked when we saw it.

“But to say that we were completely shocked would be wrong because we had been warning young people about the dangers of social media for a long time.”

Deputy headteacher Rebecca Cozens, who is also head of safeguarding at the school, told the inquest that once young people had gone “down the rabbit hole” on social media, it was a “deep one”.

Mr Sanders asked the witness if she was aware that Molly was able to access the material she did before her death. Ms Cozens replied: “Not to that extent, no.”

Questioned on whether there was an awareness of the type of material Molly had engaged with, Ms Cozens said: “I don’t think at that time an awareness of the depth of it and how quickly it would snowball… and the intensity then, when you’re going down that rabbit hole it is a deep one.”

The head of health and wellbeing at Instagram’s parent company Meta and the head of community operations at Pinterest have both apologised at the inquest for content Molly viewed.

Meta executive Elizabeth Lagone said she believed posts which the Russell family argued “encouraged” suicide were safe when the teenager viewed them.

Pinterest’s Judson Hoffman told the inquest the site was “not safe” when Molly used it.

Coroner Andrew Walker told the Russell family he would be delivering his conclusions by the end of the week.