Alan Bleasdale, along with Dennis Potter one of the truly original voices of British television drama, has spent the past decade in silence. His brand of epic narrative, his penchant for letting his characters talk and talk, went out of fashion when along came a generation of younger writers who nicked Yosser Hughes’s catchphrase - “I could do that” – and slipped into his slots. He has returned with this, a sweeping drama replete with all the Bleasdalian virtues: a huge cast of characters, an astute eye for the historical hinterland, and a belief that human decency abides in unexpected places. In this case, a German U-boat.