After a couple of years that have seen a seemingly endless string of new centrist parties, usually with more Twitter followers than voters, last week finally saw the formation of The Independent Group, which at the very least has MPs and, for now, a substantial media presence.

Early polling on TIG is difficult to interpret because it isn’t yet a party, and depending on how you phrase the question, their support ranges from six to 14 per cent.

This story will be interesting to watch, but it does raise a bigger question – what is centrism? The use of the term is becoming somewhat loose. The classical definition of the term refers solely to the economic dimension – being neither left- nor right-wing.

Current UK usage corresponds to a definition more along the lines of “a philosophy defined by being socially liberal or pro-EU rather than by being economically left or right-wing”. In other words, an economic platform consistent with centrism, but primarily a socially liberal centrism. The centre in the true sense is quite a lot broader than that.

To explore the two dimensions, we can construct measures for them using the latest British Election Study data. The economic axis is based on attitudes to free markets, inequality, redistribution, and so on. The cultural axis is derived from questions on traditional values, tolerance, diversity and capital punishment.