The Pret a Manger Christmas menu launches across the UK today, and with it the stories of five ho

For years, a growing number of scientists have been fascinated by what happens to humans when we sing in groups. What’s so magical about the simple act of singing together with other people? Why - and how - does it transform some people’s lives?

Erica has been volunteering for the South London choir for a year and a half, as a music helper. Here she is, in her own words.