So what does constitute ‘professional’ for a choir, in that case? Is it the personnel? Or the conductor? The venues in which they perform?

One answer may be camaraderie: Crouch End Festival Chorus is a good example of a ‘lifestyle’ choir – a group of singers that changes shape to suit the music it is performing and performs the variety of music it does in order to create and maintain an enthusiasm in its members that matches that of its conductor.

It’s a very simple distinction, and one that many performers and listeners would not bother either to make or to question, but what is the difference, in music, between ‘professional’ and ‘amateur’? Professional orchestras in particular are easy to define: by and large, their members are full-time, paid instrumentalists who have most likely been in intensive study of their instrument since they were young children. And although amateur orchestras can range upwards in standard and ability from the very basic, their performance homes are generally smaller and less prestigious venues than their professional cousins, and their identity is rooted more in their own enjoyment of the music they come together to play.

Choirs, though, occupy a grey area in terms of professional and amateur music-making, and looking to characterise a ‘professional’ choir requires a definition that looks further than the simple details of whether or not its members are being paid to be there, or have non-related day jobs.