Christianity as a religion is one that was first brought to the British Isles around 1st century AD, this was during the Roman Empire. Britain had its own set of religious icons; Pagan gods of the earth and Roman gods of the sky. It was into this setting that Christianity arrived, and It is thought to have started in England before moving to Ireland, Scotland, and then into other British Isles. This evangelization was carried out mostly by the Gregorian Missionaries; this eventually led to the beginning of the Church of England.
The Church of England which is the foremost form of Christianity in England has it beginnings towards the end of the 6th century, during the time of the Anglo-Saxons. The Church of England highlights continuity “through apostolic succession and traditionally looks to these early events for its origins rather than to changes brought about by the English reformation. Events such as Henry VIII’s schism with the Roman Catholic Church or the excommunication of Elizabeth I or the wider Reformation in mainland Europe are all events that contributed to the development of the Church of England as it is now established, but are regarded as a continuation of the arrival of the One, Holy, Catholic, and Apostolic Church to the British Isles.”  – Wikipedia articles on the origins of the Church of England.
However, as the years progressed the notion was formed that the Church was founded by God and the ruling monarch was automatically the Head of the Church, appointed also by God. Christianity rose from a small religion to being the national religion, with the association of Church to Monarchy. This therefore meant that all proceedings within the Kingdom were ‘governed’ by God. Christianity was a part of the people and the people were conditioned into the lifestyle of being Christians. Children were being baptized, taught in the faith as part of daily living as well as in school curriculum. Births, Marriages and Deaths/Funerals were conducted and registered by the Clergy. Therefore during this period, England was predominantly a Christian nation. It is worth mentioning that there was also paganism in England, however as Christianity grew paganism reduced.
The discussion in this essay however, is not about the origins of Christianity nor is it about the origins of the Church of England. Some of the points discussed below are from personal findings, while other points are secondary research.
With the herald of a more accommodating society, more religions are being rooted in the British society. This is also because of the increase in the ethnic groups in England, who have various religions, and with the world of political correctness; other religions are blooming and thriving as well. Unfortunately, the percentage of English people of Christian origins are dwindling, leaving generations after them to being less keen about religion altogether. Christianity is slowly diminishing because we are now in a more secular society. There are less faith schools, and the percentage of Church goers has reduced over the last couple of decades. According to personal findings, Church buildings are been sold or remodelled to other functionalities.
In current times, even though England is officially a Christian country, there are less than 40% of the people who are Christians and even few much less of them are a part of the Church of England. The remaining population are either Atheists or of a different religion. Findings have proved that the Church today has lost about 1 in 10 members are from 1996 to present day, at this rate the church will find it hard to survive in the next 50 years. There is now a massive fall in registered Births, Marriages and Deaths in the Church.
The church today is been grounded by challenges from a changing society, where the Christian institution is on a decline as well as challenges from a rise in cultural and religious diversification.
BBC sources record that the United Kingdom, which England is a part of “is ethnically diverse, partly as a legacy of empire. Lately, the country has been struggling with issues revolving around multiculturalism, immigration and national identity. This is against a background concerns about terrorism and political and religious radicalismaˆ¦” 
In conclusion, we can accept that England is still officially a Christian country due to the fact that the Anglican Church is rooted in England and that the monarchy is associated with the Church of England, however it will be hard for Christianity to hold its footing if the Church does not rise up and take a stand.
2 . http://www.bbc.co.uk/religion/religions/christianity/history/uk_1.shtml