Naman Ramachandran Comcast’s Sky Arts channel that goes free-to-air from Thursday has announced four new original program commissions including from “Trainspotting” writer Irvine Welsh and “Bulletproof” star Ashley Walters.In “Offended by Irvine Welsh,” the author explores the nature of offence and its impact and sets out to reclaim the right to offend, but not abuse, as an essential tool for artists.