Pop music is on 'a slow but unmistakable descent into pornography', according to hit songwriter Mike Stock. Stock, who was responsible for dozens of hits as part of Stock, Aitken and Waterman and helped launch Kylie Minogue's pop career, put some of the blame on the rise of stars including Rihanna, Lady Gaga and Katy Perry. He said they were among a wave of performers who 'have taken sexualised imagery, dance moves and lyrical content way beyond the limits of decency'.