The half that France didn't.
Lore has it that they divided up former Ottoman Turk territory acquired after WWI ended by drawing lines on a napkin during dinner. That's why most of those countries make no sense geographically in relation to ethnicity and why the borders are mostly straight lines and why what we now call "Arabs" used to be called "Turkish" a century ago (the only real Arabs are, ironically, called, "Saudis." There is a smattering of true Arabs spread in countries throughout the region as well, but basically most people called, "Arabs," aren't).
Britain also carved up Central Asia/Iran between themselves and Russia in the Great Game. All those countries ending in "stan" are former Iranian territory. Then you continue on into the rest of Asia, like India and... Well, you get the picture. Those immigrants aren't immigrants. They're former British subjects. Straight from the Empire on which the Sun never sets. How's that Sun looking now? Dwindling a bit, innit?
They reaped what they sowed. Just like the Bible sayeth.
Oh, and it gets better. Islam actually used to be pretty laid back, much like Christianity is today. And that at a time when Christianity in Europe was still busy burning people at the stake for not believing the Earth was flat.
As a tool against the spread of (Soviet) Socialism and (pan-Arabic) Nasserism, the UK and US funded and promoted radical fundamentalist movements like Wahhabism. We also trained them how to be terrorists. That's why you didn't hear about none of this stuff happening a century ago around there, because there was none of this stuff happening a century ago around there.
They reaped what they sowed. Just like the Bible sayeth.
