For many years there was an artificial division between 'identity' and 'class' politics and a ferocious dialogue of the deaf between people holding polarised views. Then Kimberlé Crenshaw, a professor of law and a seasoned civil rights activist argued that it was not 'either/or' but that oppressions and exploitations exist simultaneously and that rather than being purely cumulative in their effects, they are capable of interacting in a way that multiplies their impact.