Len Goodman takes to the dance floor to discover the golden age of ballroom, as the head judge of Strictly Come Dancing recalls the time when Britain went ballroom barmy. In the early 20th century millions enjoyed dancing. Graceful movement was everything as we grappled with the waltz, the tango and each other. Len also reveals a surprising world of scandal and outrage - a time when ballroom was considered radical and trendy. What was it about ballroom that people enjoyed so much and why did we eventually turn our backs on what Len considers the greatest dance form of all? Len visits Blackpool, the spiritual home of ballroom, and demonstrates some popular steps with professional dancer Erin Boag. He discovers how the smart set danced the night away at the Café de Paris and returns to a favourite dance hall from his youth, the Rivoli in south London. Len talks to dancers, singers and musicians who remember the golden age and discovers the people who introduced 'rules' to ballroom - the dance leaders and teachers who were concerned that ballroom was out of control and needed new regulations to govern steps, movement and music.