The problem lies not in the rules, but in their enforcement. I can't speak for the UK but in France it is not allowed for an intern to work more than 40 hours

The problem lies not in the rules, but in their enforcement. I can't speak for the UK but in France it is not allowed for an intern to work more than 40 hours a week under any circumstances, yet in many industries you still see 60+h workweeks as a standard for interns... Because by any means, an intern subject to this kind of unacceptable working conditions will not speak up since that would annihilate his chances to get a job at the end of his internship (and might even discredit him at other companies in the same industry)