Take 800 amateur singers, one conductor and lock them in the New Theatre for a day to learn and then perform Fauré’s Requiem that night in front of an audience of 1000. David Lawrence is in The Guinness Book of Records for conducting the UK’s largest choir — 6,846 singers! So taking on 800 should be a doddle. But David knows that whether it’s 8,000 or 800 it’s still a mammoth task that he’s undertaking — and one that he relishes.

The doyen of large choirs, David’s reputation proceeds him, and he’s in huge demand all over the world. Yet when approached to orchestrate the Macmillan event he jumped at the chance.

“I don’t know what it is about me, but I do love working with really big choirs,” David says. “What my therapist would say about that I don’t know, because I have developed a bit of a niche for myself and have done 13 or 14 concerts like this so far this year. But I would rather be pigeon-holed and known for something, than not work, and luckily there is great variety between the pigeon-holes.”

David’s posts include Associate Conductor of the City of Birmingham Symphony Chorus and Choir Leader of the City of Birmingham Young Voices, as well as managing to get 6,846 children singing a record-breaking carol medley. So how does he hold it all together? “If there’s a secret, it’s to keep them busy and make sure the rehearsal is pacy so you can’t pause for long.”

And does David ever lose his temper? “Well there was a teenage boy sitting in the front row of a concert I did recently who picked his nose all the way through and it was so off-putting I had to get him moved. And in Manchester I had 7,500 children in the choir and 12,000 parents, and the parents started heckling me.”

On Sunday, David’s ‘choir’ will range from those who have never sung before, to some of the best choral societies in the country. “We have also deliberately chosen a piece that experienced singers will have sung before, because to be honest it’s the logistics that take up all the energy. So while it’s a risky thing to do, I make sure I pace myself and find it a wonderful pressure to do it all in a certain amount of time. It doesn't have to be note perfect, that's not the point of the day.”

Voices of Macmillan will perform at the New Theatre on Sunday. For further information ring 0844 8713020.