This worthwhile centenary documentary centres on the influence on Britten's music of the lifelong leftwing convictions, pacifism and hatred of cruelty that were engendered by his education at the progressive Gresham's school in Holt, East Anglia, the alma mater of WH Auden and Donald Maclean. The case is well argued. There are useful contributions from, among others, the composer and teacher Joseph Horowitz and the cellist Anita Lasker Wallfisch (former inmate of Auschwitz, who heard him accompany Yehudi Menuhin at Belsen after the liberation in 1945). The music is well chosen and performed. John Hurt delivers the commentary with characteristic authority. Unfortunately, the dramatised sequences are acted with stilted tentativeness.