The Duke of Cambridge is planning to contact the family of 14-year-old Molly Russell, who took her own life after viewing disturbing material online, it is understood.

Prince William is expected to reach out to the teenager’s relatives by letter this week as part of his work around cyber-bullying.

Molly, from Harrow, north-west London, was found to have viewed content on social media linked to anxiety, depression, self-harm and suicide before ending her life in November 2017.

The duke has previously spoken out about social media companies and their responsibilities to stop the spread of harmful material online.

In a speech at BBC Broadcasting House in London in November, he accused tech giants of “being on the back foot” when tackling issues such as cyber bullying, fake news and hate speech.

“The noise of shareholders, bottom lines, and profits is distracting them from the values that made them so successful in the first place,” he said.

“They are so proud of what they have built that they cannot hear the growing concern from their users.”

Earlier this month, a pre-inquest review hearing heard police were confident they could access Molly’s electronic devices to view the data.