‘When I was in my first year in the choir, it snowed on Christmas Day,” remembers senior Christ Church Cathedral chorister, 13-year-old Felix Scott-Copeland. “We went out into the school playground and had a snowball fight for about half an hour. It was really fun. Then we got into our robes, and did the Christmas services.”

It’s a thoroughly colourful Christmas scene. Yet much hard work goes on behind the traditional spectacle of flickering candles and Cathedral choir members dressed in red and white robes. When arranging to meet Felix and fellow chorister Harry Brown, aged 12, I’m warmly welcomed to a rehearsal – at 8am. I wimp out, and instead ask Harry to describe his working day when we talk considerably later in the day.

“We get up at 6.30am, have breakfast at 7am, have music practice on our instruments, go over to the cathedral for a rehearsal, and come back at 9am. That’s followed by a normal school day, then further music practice, and a second daily rehearsal in the cathedral. “Then there’s a service for an hour, and we get back again at 7pm. Supper comes next, then prep, then we have free time. We go to bed at 9.10pm.”

Over the Christmas period, the choir will give two Christmas at Christ Church concerts (on December 14 and 20) and another concert in London, as well as singing in two Services of Nine Lessons and Carols (on December 23 and 24) in the cathedral. How much overlap in musical repertoire is there between these various events, I ask director of music Stephen Darlington.

“I try to have quite a large repertory from which I can select appropriate pieces for the different contexts. There is a fair amount of overlap for practical reasons, and also people like lots of familiar carols. But every year there will be two or three new pieces – this year, for instance, there will be a new work by Timothy Blinko, the father of one of our choristers. And we’re also going to do a piece by Martin Bruce, the Headmaster of our choir school.”

Stephen Darlington cites A Spotless Rose, In The Bleak Midwinter, and Tomorrow Shall Be My Dancing Day as personal favourites from the traditional carol repertoire. But has he ever received a hostile reaction to anything he’s programmed?

“There is one particular piece, The Shepherd’s Carol, by Benjamin Britten which I’ve occasionally done. It’s beautiful, but people have ‘complex’ responses to it, shall we say.”

And how about the choristers? Singing The Holly and the Ivy for the umpteenth time could get a bit boring, so do they prefer something more up-to-date?

“Yes,” Felix replies, “Because new music makes you work harder, and there’s a nice feeling at the end when you think: ‘yes, I’ve nailed it’. You can tell whether you have in fact nailed it from Dr D’s expression: he’s usually smiling, but there’s the occasional time when you think: ‘Oh, No!’”

The Service of Nine Lessons and Carols usually begins with a boy soloist singing the first verse of Once in Royal David’s City unaccompanied. At King’s College, Cambridge, on Christmas Eve, the soloist is traditionally chosen right at the last minute, just as the BBC’s red cue-light starts flashing, to avoid nerves. Do Harry and Felix think that’s a good idea?

“I think it’s better to have time to practise it in advance, even if you’re going to be more nervous,” says Felix – who, Harry reveals, normally gets the job because he’s got perfect pitch.

Both Felix and Harry profess not to have Christmas present wishlists. “But do their thoughts ever wander in that direction, perhaps during the speech sections of the Christmas concerts and services?

“Yes,” both immediately admit with laughter. “But it doesn’t happen that much,” Felix adds, “It’s probably more the case with boys who are slightly younger. Also, the readings are much more interesting at Christmas: there are some really funny poems, for instance.”

By the time that the last notes of the last carol die away on Christmas Eve, Stephen Darlington says, everyone involved is pretty exhausted.

“The singers are usually on their knees by that point! In order for it to be a magical experience for the audiences and congregations who come, you’ve got to be on your mettle all the time. For my own part, adrenaline keeps me going, but my family allege that I usually fall asleep at about 3pm on Christmas Day!”