England, by nature, has always been a fairly religious country. The Royal family are strongly Christian, as is most of the population. Due to this most people are born and brought up in Christian families, leaving them no choice about what religion they are. A lot of other religions have been introduced to England as well, the Muslim religion in particular. However, the percent of people in England who are religious is dropping greatly in recent years due to many different factors.
Both of my Grandmothers were strict Catholics and both my Granfathers were atheists. My father was born and raised a Christian, however, when he reached his teenage years he decided the religious route wasn't for him and became an atheist, against his mother's and sister's wishes.
My mother's parents decided they'd let her decide what religion she wanted to be, so brought her up an atheist, and this she remained.
Due to this both my brother and me were brought up as atheists.