The Muslim population in Europe will increase from five to 20 percent by the year 2050.
Britain, Spain and Holland will have an even higher percentage of Muslims before that time, according to a study by the London Telegraph.
Experts say there has not been much debate on how population changes will affect education and housing.
America's Pew Forum on Religion & Public Life, part of the non-partisan Pew Research Center, said in a report: "These (EU) countries possess deep historical, cultural, religious and linguistic traditions. Injecting hundreds of thousands, and in some cases millions, of people who look, speak and act differently into these settings often makes for a difficult social fit."
Some analysts say the British government and the European Union has not paid enough attention to this potential "demographic time bomb".