I see John Cleese has unleashed a shítstorm by the simple expedient of stating a fact

[Burney]

A quick google shows that according to the 2011 census 36.7% of Londoners were foreign born.

No idea what it is now but a jump to > 50% in 8 years would seem pretty surprising

Non-indigenous does not mean foreign-born.

And, by the way, 36.7% of your capital's population being foreign-born is an absolutely fúcking massive number. And, given our immigration rates over the last 8 years, plus white flight, plus the fact that the vast majority of migrants will gravitate to London because that's where the jobs are, a rate of 50% is by no means out of the question by the time of the next census in 2021.