The average British Muslim will officially have 3 kids ( we know they would have 5 kids if where possible )
the UK's average birth rate is 1.80. I could not easy find the birth rates for the white British demographic.
So Muslim population in the UK could triple in 30 years.
I have head that when foreigners are removed from the 1.8 stats the japans birth rate is higher than that of the white British. Japan was a 1.44 in 2014.