A suicide forum linked to multiple deaths in Britain has been ruled in breach of the Online Safety Act after it failed to properly block access to UK users when ordered to do so last year.

Ofcom, the online regulator, said it could now apply to the courts to issue fines and demand internet service providers block access to the site in the UK. This will depend on how the site responds over the next 10 days.

Coroners have been raising concerns about the links between the forum and suicides in the UK since at least 2019, campaigners said. The family of 17-year-old Vlad Nikolin-Caisley, from Southampton, said he took his own life in 2024 after using the site, which Ofcom is not naming.

Ofcom launched an investigation in April last year as encouraging or assisting suicide is a criminal offence in the UK.

The forum implemented a geoblock to restrict access by people on devices that appear to be physically located in the UK, but also posted a message on the landing page promoting ways to circumvent the block. This was removed, but in November, Samaritans found the forum remained directly available to UK users via a “mirror site” – the same site with a different domain name.

Bereaved families and the Molly Rose Foundation – which was set up after Molly Russell, 14, took her own life after being sucked into harmful social media content – complained that the regulator was not moving fast enough and said last autumn that there were “serious questions to answer about why Ofcom has delayed taking action on multiple breaches of the law”.

Their analysis found coroners had raised concerns about various substance or suicide forums with government departments at least 65 times since 2019. It also said there was evidence of deaths linked to the forum that had occurred in the UK since the geoblock.

Ofcom has now found that the forum failed to comply with its duties under the Online Safety Act. This includes assessing the risk of illegal content and swiftly taking down illegal content when it became aware of it.

The regulator said: “After a period of monitoring the service, we became concerned that the block was ineffective and/or was not consistently maintained, and continued to a provisional breach decision as a result,. The provider of the forum now has 10 working days to respond to our provisional findings, which will be carefully considered before we make our final decision.”

Andy Burrows, the chief executive of the Molly Rose Foundation, said: “This forum exists to coerce and groom vulnerable, often young, people into ending their lives and this action from Ofcom couldn’t come soon enough. It is now crucial that the regulator acts swiftly to shut the site down with fines or criminal sanctions that match the level of harm caused.

“Working with survivors and bereaved families, we have identified at least 135 UK deaths linked to the forum. Ofcom must act decisively so there are no more lost lives.”