Social media platforms must take action to stop their algorithms recommending harmful content to children, and put robust age-checking measures in place to protect them, Ofcom has said.

The regulator has published its draft children’s safety codes of practice, which set out how it expects online services to meet their new legal responsibilities to protect children online under the Online Safety Act.

The online safety laws require sites which can be accessed by children to take action to protect those younger users by assessing the risk their platform poses to children and then putting in place measures to mitigate those risks – with large fines among the possible penalties for those found to be in breach.

Ofcom, as the new regulator for the sector, has published a range of draft codes of practice in recent months, setting out how platforms should handle different types of content, ahead of the new rules beginning to come into full force, which is expected towards the end of this year.

The latest codes include more than 40 practical measures which Ofcom says will demand a step-change from tech firms by compelling safer design and operating practices from the biggest sites.

In particular, the codes will expect services to carry out robust age verification processes to stop children accessing harmful material, as well as ensuring that their recommendation algorithms – such as “For You” pages – do not serve dangerous or potentially harmful content to children.

Our measures, which go way beyond current industry standards, will deliver a step-change in online safety for children in the UK. Once they are in force we won’t hesitate to use our full range of enforcement powers to hold platforms to account

Under the proposals, platforms which can be accessed by children and have a higher risk of harmful content appearing must configure their algorithms to filter out the most harmful content from children’s feeds, and reduce the visibility and prominence of other lower risk, but still potentially harmful, material.

The draft codes also require firms to have content moderation systems and processes in place, and ensure that swift action is taken against harmful content, with search engines expected to have a “safe search” option for use by children.

Ofcom chief executive, Dame Melanie Dawes, said: “We want children to enjoy life online. But, for too long, their experiences have been blighted by seriously harmful content which they can’t avoid or control. Many parents share feelings of frustration and worry about how to keep their children safe. That must change.

“In line with new online safety laws, our proposed Codes firmly place the responsibility for keeping children safer on tech firms. They will need to tame aggressive algorithms that push harmful content to children in their personalised feeds and introduce age-checks so children get an experience that’s right for their age.

“Our measures, which go way beyond current industry standards, will deliver a step-change in online safety for children in the UK. Once they are in force we won’t hesitate to use our full range of enforcement powers to hold platforms to account. That’s a promise we make to children and parents today.”

Sir Peter Wanless, chief executive of children’s charity, the NSPCC, said the draft code was a “welcome step in the right direction” towards protecting children online.

“Building on the ambition in the Online Safety Act, the draft codes set appropriate, high standards and make it clear that all tech companies will have work to do to meet Ofcom’s expectations for keeping children safe,” he said.

“Tech companies will be legally required to make sure their platforms are fundamentally safe by design for children when the final code comes into effect, and we urge them to get ahead of the curve now and take immediate action to prevent inappropriate and harmful content from being shared with children and young people.

“Importantly, this draft code shows that both the Online Safety Act and effective regulation have pivotal roles to play in ensuring children can access and explore the online world safely.

“We look forward to engaging with Ofcom’s consultation and will share our safeguarding and child safety expertise to ensure that the voices and experiences of children and young people are central to decision-making and the final version of the code.”

Child online safety campaigner Ian Russell, the father of 14-year-old Molly Russell who took her own life in November 2017 after viewing harmful material on social media, said more still needed to be done to protect young people from online harms.

In his role as chair of online safety charity, the Molly Rose Foundation, Mr Russell said: “Ofcom’s task was to seize the moment and propose bold and decisive measures that can protect children from widespread but inherently preventable harm.

“The regulator has proposed some important and welcome measures, but its overall set of proposals need to be more ambitious to prevent children encountering harmful content that cost Molly’s life.

“It’s over six years since Molly’s death, but the reality is that very little has yet changed. In some respects, the risks for teens have actually got worse.

“That’s why it’s hugely important that the next Prime Minister commits to finish the job to and strengthen the Online Safety Act to give children and families the protection they deserve.”

Technology Secretary, Michelle Donelan, said: “When we passed the Online Safety Act last year, we went further than almost any other country in our bid to make the UK the safest place to be a child online.

“That task is a complex journey but one we are committed to, and our groundbreaking laws will hold tech companies to account in a way they have never before experienced.

“The Government assigned Ofcom to deliver the Act and today the regulator has been clear: platforms must introduce the kinds of age-checks young people experience in the real world and address algorithms which too readily mean they come across harmful material online.

“Once in place, these measures will bring in a fundamental change in how children in the UK experience the online world.

“I want to assure parents that protecting children is our number one priority and these laws will help keep their families safe.

“To platforms, my message is engage with us and prepare. Do not wait for enforcement and hefty fines – step up to meet your responsibilities and act now.”