Lord Carey, the former archbishop of Canterbury. (AP)

Commenting on the British government's review of communal integration in England, particularly involving Muslim communities, Lord George Carey, the former archbishop of Canterbury, said Britain is forgetting its Christian heritage, suffers from a "creeping culture of religious illiteracy," and added that Christianity should be included in citizenship tests for all immigrants.

"It is a preposterous yet dangerous state of affairs when Christmas cards are considered offensive, or the Cross is banned because it is thought divisive. Yet this is the world we live in," said Lord Carey in a Dec. 17 commentary for The Mail On Sunday. "We should rejoice in our Christian identity as a nation and celebrate it."

"I believe we should include Christianity in citizenship tests for all those who want to come to this country," said Lord Carey, who was the archbishop of Canterbury 1991-2002. "There are many questions asked of migrants about the Royal Family and Parliament, but little about the Church of England or Britain’s Christian history."

"And it is vital that the Government itself does its homework better," he said. "Politicians and advisers would do well to remember the contribution of Christianity to our life, and not just our ‘holy-days’ and celebrations."

"In co-ordination with religious leaders, some thought should be given to special training in religious literacy for at least some judges, Ministers and senior civil servants who deal directly with religious communities – their freedom and equalities," said Lord Carey.

The archbishop also noted that the Christian population in the Middle East has fallen from 7% in 1996 to 1.5% today. "[T]he Middle East, the region that gave birth to our faith, could soon see the virtual extinction of Christianity," said the archbishop.

As for Muslim communities in England, Lord Carey, referencing the government's recent review, said the facts show "public authorities have been ignoring harmful social practices in some of our Muslim communities, such as the exclusion of women, domestic violence, forced marriage and female genital mutilation." People do not speak out about these problems, as the review documents, because they fear being labeled "Islamaphobic."

However, the review, by Dame Louise Casey, who heads the Social Welfare office in England, "equated conservative religious views with intolerance, even extremism," said Lord Carey. "By condemning all those with conservative religious views – and not just an Islamist minority – she is imposing a new form of intolerance."

"In civil life as a whole, we are choosing to forget the Christian heritage which has contributed so greatly to our laws, rituals, language, our traditions and even our landscape," said the 81-year-old archbishop. "It has built our civil society and sustained charity and social movements and has been the fabric of our daily existence for a millennium and more."

"The glue which tied us together used to be the institutions of our civil society," he said, "inlcuding the Church of England...."