I added the context of the British Empire and the Commonwealth to point at the fact that these historical activities have transformed the UK over a period of time.
These timing of British Empire runs on for a while, but around the time when it ended post-WW2, that is when citizens of the British commonwealth countries (an institution that exists as a result of the British Empire) were invited to come and help rebuild the UK.
A couple of generations later, and London becomes one of the most diverse cities in the world.
So that is the context in which I meant the phrase “because of all this”. It’s playing out over a long time as a casual link, not all things happening at the same time.
On the 2nd question of why it is impossible for England to say no to immigration now rather than the preceding 200 years. I would offer these points.
1 - Technically, we have always had immigration. It’s a question of how much did it matter to the people at the time?
I would argue that perhaps we aren’t as familiar with British history in the 1700s as we ought to be. For example, I had no idea until a few years ago that the first Black person to vote in the UK was a person named Ignatius Sancho: https://en.wikipedia.org/wiki/Ignatius_Sancho - https://www.boughtonhouse.co.uk/sancho/
A slavery abolitionist and a composer who lived in London. Who knew?
Secondly, the reason why I think immigration is such a hot topic in the UK’s public sphere is because:
1 - The tabloid press have dedicated so much time and attention to it - https://migrationobservatory.ox.ac.uk/press/migrants-in-the-...
2 - Multiple politicians have used it to position it as a problem that they are uniquely positioned to solve (Michael Howard under the Conservatives during the 2005 Election Campaign, Nigel Farage in the 2015 UKIP election campaign).
3 - It was promoted as a problematic issue during the EU Referendum - flyers were distributed suggesting that Turkey was about to join the EU, and that 80m Turkish citizens would have the right under freedom of movement to move to the UK. It wasn’t true but the flyers were distributed anyway: https://blogs.lse.ac.uk/politicsandpolicy/unfounded-claim-tu...
So over time, the UK’s public opinion has been shaped and steered in the direction of treating immigration in a negative context.