Choirmaster Gareth Malone continues his mission to get some of Britain's busiest workplaces singing. This week he travels to the Midlands to set up final choir in one of the country's largest water companies, Severn Trent Water. Once formed, the choir will sing against three other workplace choirs as they compete for the chance to be crowned Gareth's Best Workplace choir. With over five thousand call centre staff and over five hundred workmen, dealing with everything from raw sewage and finding leaks, finding thirty people to make up the choir appears easy. But as staff are struggling to juggle family commitments and busy work schedules, things aren't plain sailing and Gareth begins to feel the pressure.