It may be formed, as Burke said, by 'a body of men united for promoting by their joint endeavours the national interest upon some particular principle in which they are all agreed.'[17] But when a party has once come into existence its fortunes depend upon facts of human nature of which deliberate thought is only one.

It is primarily a name, which, like other names, calls up when it is heard or seen an 'image' that shades imperceptibly into the voluntary realisation of its meaning.

As in other cases, emotional reactions can be set up by the name and its automatic mental associations.

It is the business of the party managers to secure that these automatic associations shall be as clear as possible, shall be shared by as large a number as possible, and shall call up as many and as strong emotions as possible.

For this purpose nothing is more generally useful than the party colour.