The service of Nine Lessons and Carols this afternoon at King’s College Cambridge has an extra resonance.

It is the last time that the choir will be conducted by Stephen Cleobury who has been responsible for the music over the last 37 years.

He was appointed Director of Music in 1982.

It is also the 100th anniversary of the Nine Lessons and Carols service being held at King’s College on Christmas Eve and the 90th anniversary of the first broadcast of the service from the chapel.

The service, invented at Truro Cathedral and first heard outside Cornwall at St Mary Lambeth, is now the start of Christmas for millions of people in the UK and abroad.

In America it is often the background to Christmas Eve breakfast. 

When does Advent become Christmas? We all have our own moment: 3pm when BBC Radio 4 broadcasts the service from King’s and the first verse of Once in Royal David’s City is heard; vespers; evening prayer; the First Mass of Christmas about 6pm or Midnight Mass.

Whatever the moment, it is the start of tomorrow and the twelve days of Christmas.