Prince William has accused social media giants of being “on the back foot” when it comes to tackling issues like fake news, privacy and cyber-bullying.

In a hard-hitting speech he said technology firms “still have a great deal to learn” about their responsibilities and he challenged them to fight harder against poison spread online.

William said he believed tech leaders were “people of integrity” but said they appeared to be unwilling to properly tackle issues amplified by the platforms – from cyber-bullying and misinformation to privacy and hate speech.

He was speaking during a visit to the BBC in London to view the work the broadcaster is doing as a member of his Taskforce on the Prevention of Cyberbullying.

He said much of the widespread optimism when the internet first became a staple of life over a decade ago has given way to concern and fear.

William said: “We have seen that the technology that can allow you to develop an online community around a shared hobby or interest can also be used to organise violence.

“The platform that can allow you to celebrate diversity can also be used to cocoon yourself in a cultural and political echo chamber.

“The new ways we have to access news from across the world are also allowing misinformation and conspiracy to pollute the public sphere.

“And the apps we use to make new friends can also allow bullies to follow their targets even after they have left the classroom or the playing field.”

William, who was with the Duchess of Cambridge, set up his taskforce to stop cyber-bullying among schoolchildren in May 2016.

The couple met youths who wrote and performed a new video for Stop, Speak, Support, a campaign being introduced in schools providing guidance for children on what to do when they see bullying online.

William said he had been moved after meeting bereaved parents of bullied children who had taken their own lives.

He said social media companies had “done more to connect the world than has ever been achieved in human history”.

But he added: “I am worried, though, that our technology companies still have a great deal to learn about the responsibilities that come with their significant power.

“I say this not in anger. Again, I believe our tech leaders are people of integrity who are bringing many benefits to our lives and societies.

“I am very concerned though that on every challenge they face – fake news, extremism, polarisation, hate speech, trolling, mental health, privacy, and bullying – our tech leaders seem to be on the back foot.

“Their self-image is so grounded in their positive power for good that they seem unable to engage in constructive discussion about the social problems they are creating.”