Two fundamental questions arise when considering the topic of British choral life: what exactly constitutes a choir and where do the boundaries of choral music lie? How many people do you need before you call a group of singers a choir rather than a vocal ensemble? Asked to define a ‘choir’ and a ‘choral sound’, many would say that its essence lay in the doubling of voices on the individual parts, so that eight voices might be considered a minimum for a group singing in four parts. That said, church choirs may be found with fewer numbers, either from the lack of recruits, or as a deliberate choice by those churches who perhaps employ a professional quartet of singers – such a group may fulfil the functions of a choir, even though the resulting sound is not one which would necessarily be described as ‘choral’. The doubling of parts, however, is not always a pre-requisite for a ‘choral sound’; it is also partly a question of texture. Although a four-part work sung by single voices may not sound ‘choral’, an eight-part one sung this way comes much closer. And all would agree that Tallis's forty-part motet, ‘Spem in alium’, originally conceived for, and still usually sung by single voices, is certainly a choral work. Nevertheless, however undefined the borderline, there is a generally recognized distinction between what are called vocal ensembles and choirs. While no-one would call the six voices of The King's Singers a choir, by the time you get to the eponymously named The Sixteen, that is undoubtedly one, even if of ‘chamber’ size. The one thing that perhaps defines any sort of choir, as opposed to the singing of a church congregation or a football crowd, is that is pre-supposes a degree of rehearsal, or at least the exercising of already acquired skills.