Abba’s Björn Ulvaeus, the actor Julianne Moore and the Radiohead singer Thom Yorke are among 10,500 signatories of a statement from the creative industries warning artificial intelligence companies that unlicensed use of their work is a “major, unjust threat” to artists’ livelihoods.

The statement comes amid legal battles between creative professionals and tech firms over the use of their work to train AI models such as ChatGPT and claims that using their intellectual property without permission is a breach of copyright.

“The unlicensed use of creative works for training generative AI is a major, unjust threat to the livelihoods of the people behind those works, and must not be permitted,” reads the statement.

Thousands of creative professionals from the worlds of literature, music, film, theatre and television have given their backing to the statement, with authors including Kazuo Ishiguro, Ann Patchett, and Kate Mosse, musicians including the Cure’s Robert Smith as well as the composer Max Richter and actors including Kevin Bacon, Rosario Dawson and F Murray Abraham.

The organiser of the letter, the British composer and former AI executive Ed Newton-Rex, said people who make a living from creative work are “very worried” about the situation.

“There are three key resources that generative AI companies need to build AI models: people, compute, and data. They spend vast sums on the first two – sometimes a million dollars per engineer, and up to a billion dollars per model. But they expect to take the third – training data – for free,” he said.

Newton-Rex is a former head of audio at tech firm Stability AI but resigned last year over the firm’s belief that taking copyrighted content to train AI models without a licence constitutes “fair use”, a term under US copyright law meaning permission from the copyright owner is not needed.

Newton-Rex added: “When AI companies call this ‘training data’, they dehumanise it. What we’re talking about is people’s work – their writing, their art, their music.”

In the US John Grisham, Jodi Picoult and George RR Martin are among a group of authors suing ChatGPT developer OpenAI for alleged breach of copyright, while artists are also suing tech firms behind image generators and major record labels including Sony Music, Universal Music Group and Warner Music Group are suing AI music creators Suno and Udio.

Newton-Rex also warned that an “opt-out” proposal for scraping content being considered by the UK government would be highly damaging. This month the Financial Times reported that ministers would consult on a scheme that would allow AI firms to scrape content from artists and publishers unless they “opt out” of the process.

Last month Google, a major player in AI, called for the relaxation of restrictions on a practice in the UK known as text and data mining (TDM), where copying of copyrighted work is allowed for non-commercial purposes such as academic research.

Newton-Rex said the opt-out option was flawed because most people are unaware of such schemes.

“I have run opt-out schemes for AI companies,” said Newton-Rex. “Even the most well-run opt-out schemes get missed by most people who have the chance to opt out. You never hear about it, you miss the email.

“It’s totally unfair to put the burden of opting out of AI training on the creator whose work is being trained on. If a government really thought this was a good thing for creators then it would create an opt-in scheme.”

Newton-Rex said the number of signatories to the statement, and the breadth of creative talent they represent, made clear that an opt-out scheme would be considered “totally unfair” by creators.

The statement is also signed by creative industry organisations and companies including the American Federation of Musicians, the US actors’ union SAG-AFTRA, the European Writers’ Council and Universal Music Group.

A spokesperson for the UK government said meetings had been held with AI firms and the creative industries over copyright, adding that it was an area which “requires thoughtful engagement, and as part of that we are determined to hear a broad range of views to help inform our approach”.