For those who have trouble assimilating the idea that in British English the r is only pronounced when it’s followed by a vowel sound, here is an enlightening clip. Notice how the parts in red are not pronounced:

  Why when as a nation we’re becoming more and more irreligious, is there more and more religion in our schools. Find out (Laurie Taylor, BBC4).

If you want to remember when the r is pronounced and when isn’t, you’ll find all the necessary information here.

Cheers,