>> They weren’t different enough from the British population to have any noticeable effect

>You have a very odd view of life in the UK if you believe this.

If all 250,000 Britons in the UAE returned to the UK in the next three months I would expect it to have no noticeable effect a year from now. By the same token I wouldn’t expect much from 100,000 Brits moving from India to the UK in 1947. West Indian migration starting in the 1960s or Ugandan Indians in the 1970s are movements of people who are genuinely different in important ways.

Those had no great effect on the civil service culture either.