I think the issue is actually the lack of a law. The current law basically says it's illegal to film women who are nude without their consent. But, the court said these women weren't nude so according to current law its legal. The guy was taking upskirts of women sitting on a trolley. In some ways I think it would be hard to define a law that outlaws, since you'd essentially be saying its illegal to take a picture in public, of something that is publicly visible depending on the angle.