Sophocles, Dennis Potter, The painter El Greco. Not the usual collection of influences that go towards shaping an album, but then Trembling Bells are not your usual sort of band. The Sovereign Self is a remarkable work from remarkable musicians - one of Britain's most distinctive and exciting groups. "It's darker than our other records" says Alex Neilson, the five-piece band's drummer and principal songwriter. "Suffering played quite a big part in its conception. I came out of a relationship and was consoling myself creatively and emotionally by reading a lot of Greek tragedy. The language is incredible. I immersed myself in that and then cherry-picked lines from it, distorting and personalising them." The Sovereign Self - named after a line from Dennis Potter, the late television auteur - is the fifth album from Glasgow's Trembling Bells, their first since 2012's The Marble Downs, a collaboration with Will Oldham. It is a driving, dramatic and at times hallucinatory work, filled with a great sense of tension and release; a witches' brew, a psychedelic stew mixing up the range of the band's musical interests - everything from ramshackled ballads to ancient May Day chants, swaggering acid rock to swirling prog epics.