For years now, executives at companies that are pouring hundreds of billions of dollars a year into developing various artificial intelligence tools have insisted that the technology will ultimately mean people will spend less of their time working.

An engineering director at Google said four years ago that AI would deliver a four-day work week by 2025.

Earlier this year, and just one year after that engineering director's prediction, OpenAI took up the challenge, in a manner of speaking. It formally urged companies to start testing out a four-day work week (with no change in pay), claiming that AI will soon be able to speed up so much human labour that the corporate world should prepare itself.

However, a former OpenAI technical employee who left the company last year told the BBC the firm never actually trialled the four-day work week it suggested others should try while they were there.

Instead, the person described what was often a gruelling work culture marked by frequent "crisis meetings", working on weekends, and "super cut-throat" performance reviews that would see colleagues suddenly let go.

"You go in on Saturday or Sunday just to catch up or make sure things aren't broken," the person said.