What will be the predominant religion in fifty years in UK?

Answer 1

Christian. In 2001 (from census data: http://www.statistics.gov.uk/census2001/profiles/commentaries/ethnicity.asp#religion)

There are 37.3 million people in England and Wales who state their religion as Christian. The percentage of Christians is similar between the two countries but the proportion of people who follow other religions is 6.0 per cent in England compared with 1.5 per cent in Wales. In England, 3.1 per cent of the population state their religion as Muslim (0.7 per cent in Wales), making this the most common religion after Christianity. For other religions, 1.1 per cent in England and 0.2 per cent in Wales are Hindu, 0.7 per cent in England and 0.1 per cent in Wales are Sikh, 0.5 per cent in England and 0.1 per cent in Wales are Jewish and 0.3 per cent in England and 0.2 per cent in Wales are Buddhist. In England and Wales 7.7 million people state they have no religion (14.6 per cent in England and 18.5 per cent in Wales).