More than half of Westminster's population (based on estimates but will be confirmed in the Census) were born outside of the UK. The [proportion of homes in which English is spoken is equivalent to the number of homes in which Bengali and Arabic are spoken. I suspect that the 2021 Census data will indicate that the populations of all, or almost all, London boroughs will be more than 50% BAME. Worth noting that Westminster is within the 30%-40% most deprived boroughs in the country.
London boroughs are the most diverse in the country. This is why it makes me laugh when someone on here claimed that Delta hit the NW before London due to the large number of Indians living up north. There is around eight times more Indians living in London then there are in Leicester (city with second biggest Indian population).