They aren’t. “Indian curries” are a British invention, where in the C17th onward a vast collection of dishes from disparate and very regionalised cuisines were conflated together by those in the Raj as “curries”.

These curries were adapted and created for British tastes, and were not eaten by the native populace. When men and later families came back to Britain from postings in the Raj they brought this new cuisine with them, and sometimes their cooks.

Commercial Anglo-Indian cuisine appears from the 1920s, and with the end of the colony and the partition came a wave of immigrants from Pakistan, who opened up more establishments.

The boom began with Bangladeshi refugees arriving in the 1970s, about the time when working classes were looking beyond fish and chips for “eating out”. Here British Indian Restaurant cuisine was formed, a highly modular style of cooking which allows a great degree of customisation by the customer and an economic use of ingredients.