Resolving never to be anything except ‘a poet’, Alfred Lord Tennyson wore his hair long, smoked incessantly and sported a cloak and wide-brimmed Spanish hat. The tragic loss of Arthur Hallam, a brilliant friend and fellow Apostle at Cambridge, fed into some of his most successful and best-known poems. But it took Tennyson seventeen years to complete his great elegy, In Memoriam,a work which established his fame and secured his appointment as Poet Laureate. John Batchelor tells his story.