Lethal synthetic opioids linked to more than two deaths a week in the UK have been advertised for sale in thousands of posts on social media, an investigation has found. Suppliers boasted to undercover BBC reporters posing as dealers about how easy it was to use social media to promote nitazenes, an illegal group of drugs several times more powerful than heroin. The investigation found almost 3,000 posts on the music sharing site SoundCloud giving audio clips advertising the drugs, with contact details of suppliers shown in track titles. It also found adverts for the drugs in 700 posts on X, including some that had been on the site for 18 months. In the programme New Drug Threat, which will be broadcast on BBC One on Monday, one supplier was recorded as saying: “[SoundCloud] is music platform, but we can make an advertisement on it”. Another supplier claimed X was “good to use” to promote the drugs as its adverts were less likely to be blocked on the platform. The reporters contacted 35 suppliers, including 14 who had advertised on SoundCloud and six who had advertised on X. Out of the 35 contacted, 30 were willing to post to the UK, but the reporters did not actually buy the drugs. This year, the figures released to the Guardian by the National Crime Agency showed 65 people had died from taking nitazenes in the previous six months – more than two a week. User often unwittingly take the substances, after they have been hidden in other illegal substances by dealers. One of the UK’s first victims was 21-year-old musician Dylan Rocha from Southampton, who died in July 2021 after unknowingly taking heroin that contained nitazenes. Rocha’s mother, Claire, described the findings of the investigation as shocking. She asked: “How has that been allowed to happen? How many people have died as a result of that being advertised there?” Prof Vicki Nash, the director of the Oxford Internet Institute, told the programme: “Finding adverts on this scale, hundreds, thousands of adverts, is horrifying with potentially a very significant risk to human life.” Mike Trace, a former government drug tsar, said: “In terms of drug-related deaths, the arrival of nitazenes is probably the biggest new challenge, new fear, we have. “We are currently experiencing an ‘overdose crisis’, with nearly 5,000 drug-related deaths in England and Wales each year. If nitazenes come into this market in a big way, that death rate could spiral and double or treble.” After being alerted to the adverts, SoundCloud removed almost 3,000 posts. It said it and other social media platforms were “being targeted by bad actors” and promised to do “everything” it could to “tackle this worldwide epidemic”. X also removed hundreds of posts after being contacted by the reporters, but it did not respond to request for comment.