Porcupine Tree are a progressive rock band formed by Steven Wilson in 1987 in Hemel Hempstead, Hertfordshire, England. Apart from psychedelic rock, their music has been also influenced by trance, krautrock and ambient due to Steven Wilson and Richard Barbieri's liking for the Kosmische Musik scene of the early '70s, led by bands such as Tangerine Dream, Neu! and Can. They have recently begun to lean towards metal music.