> London is a western city, because of its location and culture.

The dominant culture of the local population is not "Western" anymore.

> London has been a city of traders and other foreigners since at least the days of the Romans.

Is it?

Let's look at the official data: https://en.wikipedia.org/wiki/Demographics_of_London

Percentage of white population in London over the years:

- 1961 - 97,7%

- 1966 - 95,5%

- 1971 - 92,6%

- 1981 - 86,6%

- 1991 - 79,8%

- 2001 - 71,15%

- 2011 - 59,79%

- 2021 - 53,8%

It's clear that, up until very recently, London was a city of traders and other foreigners living there among the highly homogenous local population.