Reuters has published a useful "FactBox" on British Catholicism.
SOME NUMBERS
-- Around 5.2 million Catholics live in England and Wales, or around 9.6 percent of the population there, and nearly 700,000 in Scotland, or around 14 percent. Catholics in Northern Ireland come under the Catholic Church in all Ireland.
-- In the 2008 British Social Attitudes survey, 43.2 percent of those responding said they had no religion. The largest church was the Church of England (22.5 percent). Other Christian groups were Presbyterians (2.9 percent), Methodists (1.9 percent) and Baptists (0.8 percent) with 10 percent listed as non-denominational or "other Protestant."
-- The main non-Christian faiths were Islam (3 per cent), Hinduism (1.5 percent) and Judaism (1.0).
HISTORY
-- Until the 1530s, Christianity in Britain came under the authority of the pope, and doctrine and worship were Catholic.
-- In 1534, after Pope Clement VII refused to annul his marriage to Catherine of Aragon, King Henry VIII had himself declared Supreme Head of the Church in England and closed down the monasteries. He continued to consider himself a Catholic.
-- After a experiment with Protestantism under his son Edward VI (1547-53) and a return to Catholicism under his elder daughter Mary I (1555-58), England officially adopted Anglicanism in 1559 under his younger daughter Elizabeth I (1558-1603). Except during the reign of the Catholic James II (1685-88), Catholicism remained illegal for the next 232 years.
-- Catholic worship became legal in 1791. The Emancipation Act of 1829 restored most civil rights to Catholics.
-- In the 1840s, the ranks of Catholics were augmented by Irish immigration after the Irish Famine and by Tractarian converts from the Church of England, who included the future cardinals John Henry Newman and Henry Edward Manning.
RELATIONS WITH CATHOLICISM
-- The Act of Settlement of 1701, later extended to Scotland, bars Catholics from the British throne. It is still in force.
-- Britain restored links with the Vatican in 1914 after a break of 350 years and raised this to full diplomatic status in 1982. Francis Campbell, the first Roman Catholic appointed ambassador to the Vatican for 400 years, presented his credentials to Pope Benedict in December 2005.