Jack Thorne, one of Britain’s most successful screen and stage writers, has warned that some people in his profession are using AI “to cheat”, as he called for laws banning the secret use of the technology to generate scripts.

Thorne, who co-wrote the hit Netflix drama Adolescence and wrote the stage play Harry Potter and the Cursed Child, said that “writers need to be squeaky clean” in the face of AI models that “steal” the creative industry’s work.

In a wide-ranging speech in London, Thorne attacked government inaction over the AI industry’s mass-scraping of material to train their models. He said Keir Starmer’s government had been “a bit dazzled by tech” and lamented a failure to protect the copyright of writers.

However, he also said he had heard worrying stories about the misuse of AI among writers that risked undermining the profession.

“I have spoken to a number of execs and studio heads about their use of AI, and got hugely different responses, but what I did hear from them – and what anecdotally I’ve heard from a few writers close to me – is that some in my profession are using AI to cheat,” he said.

“What I’m not talking about here is using AI to help – to discuss things with, to check for spelling errors or help with layout. I’m talking about using AI as a replacement for endeavour, as a replacement for writing at all. Using prompts instead of writing words.

“That is, simply put, failing to write, they’re cheating their employers in doing so, and they’re cheating their fellow writers.”

Thorne, who is the president of the Writers’ Guild of Great Britain, warned that “if publishers, studios, streamers, can point to the writer as the problem, that gives them the excuse to behave however they’d like with content”.

He added: “Passing AI work off as your own needs to be unlawful. If you use AI to generate content and you do not declare it as such, then that is fraud and the companies you do it to should be entitled to prosecute you.

“To discourage it, the impact should be sizeable, and that requires laws but also us as an industry responding. Just as it should get you threatened with expulsion at university if you use it for essays, so it should have some professional impact on your career if you use it for text.”

Thorne said broadcasters such as the BBC and Channel 4 should threaten sanctions against those found to have used AI to generate their work.

“To protect the most vulnerable, it is essential,” he said. “As writers, what we are is what we make, and both the law and our industry should be absolutely crystal clear on that.”

Thorne also said AI must not be allowed to impersonate actors, directors and writers.

He criticised inaction by the government to protect the intellectual property of writers from AI models and said the way ministers acted in the next five years “will define what the next hundred years looks like for every writer in this country”.

Last year, Starmer’s government abandoned a proposal that would have required artists and copyright holders to actively opt out of having their material fed into AI systems, after a backlash. Ministers instead held a consultation on the issue.

“There are so many things the government could be doing,” Thorne said. “Crucially, observation without intervention for fear of upsetting their apple cart could be replaced by observation with intervention for fear of upsetting our apple cart.

“The pieces of AI we use cannot be built using thievery. Cannot be built on a copyright crime. That’s what government is there for, to set lines in an argument. While adaptation is probably necessary, legislating so that you are protecting us from the worst excesses is essential.”

He added: “This requires government leadership. In fact, it requires our government to take global leadership.”

A government spokesperson said: “Copyright laws must protect the UK’s position as a creative powerhouse while unlocking the extraordinary potential of AI-driven innovation. We are doing the work that’s required to get the right outcomes so both the creative and technical sectors can flourish in this country.”