Re: Mystery
What problem are you trying to solve? If you want people to be treated well in the workplace, perhaps rules that place a duty of care on *all* businesses covering *every* human being they directly or indirectly engage in whatever capacity might be a better approach.
A self-employed electrical engineer replacing the light bulbs in an office can be harassed while onsite by permanent employees. That’s not acceptable. A well-paid one-of-a-kind specialist consultant operating through a PSC who has been hired to solve a specific problem (a “legitimate” contractor according to some) can be bullied by under pressure senior managers with unreasonable expectations. That’s also not acceptable.
I agree things need improving, such as regulation of umbrellas, end-clients liable for employer NI and limiting the duration of any worker-client engagement before full employment rights are due.
But trying to shut down legitimate businesses offering a legitimate service with legitimate use cases which can offer flexibility valued by workers and end-clients, and are no different to agency "temping" that's been around for decades, isn't the answer.