Rubbish, there's NO "silent conspiracy" taking place. The percentages do not align with a slow take-over theory.
Sounds more like what far-right groups propagate.
In reality, particularly in the UK the percentages of overall citizenship in Western Europe of sub-continent ethnicity are insignificant. Western countries allowing migration is purely based on economic grounds.
Analytically, figures of sub-continent migration compared with the averaging of time periods of around 6 or 7 decades, actually correlates to a sustained controlled migration policy. This is further compounded by ever-growing migration controls and skills-based points systems emerging, coupled with extreme resistance from natives on mass migration. The evidence is evident, Western policies to control mass migration is mature, with loop-holes and grey policies being removed.
It's safe to assume migration either skills-based or through war-torn regions will not change the current demography, and natives will remain dominant with only exceptional talent from minority groups pushed towards influential positions.
Furthermore, cultural cohesion in Western cities has failed, with varied ethnic groups living in "cluster" societies and ever-increasing trends of discrimination stemming from both majority towards minority and minority on minority. Ultimately these events and patterns lead's to the presumption of a reduction of mass migration in the coming decades, with Brexit; a boom/bust economic system; terrorism; far-right views; tighter migration laws, amongst others as supportive notions.