I used to work in the UK. I once worked for a company that had a salesperson that wanted to quit. He was forced to do a non-sales job for thirty days stacking boxes and sorting old files before he was allowed to leave and he hated every minute of it.
So yes, sometimes strong labor laws have a hint of slavery to them, but certainly not equivalence to real slavery.
That unusual. He’d only be obliged to continuing his job during his notice period. Not a different job. Sounds like he didn’t know his rights.
Most UK contracts will also include a clause allowing the company to end the employment immediately as long as they still pay out what the employee would have earned during their notice period.
Having been through a few roles in the uk myself, the obligation on the company to give me adequate notice (and pay) has always benefited me.
So yes, sometimes strong labor laws have a hint of slavery to them, but certainly not equivalence to real slavery.