According to Ian Anderson of the rock band Jethro Tull, it is “a strange, pragmatic poetry”. “A wonderful sedative,” reckoned Blur’s Damon Albarn. “We love it without really knowing what it means most of the time,” declared the poet, Sean Street. They could only have been talking about the BBC shipping forecast, a fixture of the station’s output for the past 90 years, the subject of countless poems, pop songs and choral works and now the subject of a spirited half-hour (23 April) by the folk singer Lisa Knapp.To Knapp, who performed one or two of her own tributes to Lundy and Malin, the shipping forecast had been a constant in her life, conveying an agreeable sense of “being cosseted … while all these nautical dramas are being e