Minimum wage for interns?

We are looking to get a "Ministry Intern" with a focus on any of Youth Work, Children’s Work or Media. I'm not sure of the legalities of this kind of appointment, for example: it's not strictly an apprenticeship but would National Minimum Wage apply?; are interns classified as "workers" or "employees" or is this even the right question?; is this classified as "work experience"? plus a thousand other questions.

Does anyone have any wisdom on this, please? William Small