Some Catholics were jubilant at this apparent breach in the fortifications of the established church. 'I am beginning to believe that there really is a conversion of England under way, and unseen powers are at work here,' said Cristina Odone, editor of the Catholic Herald.
The Duchess's husband, the Duke of Kent, is 18th in line to the throne. His office pointed out that the Duchess's decision had no constitutional implications whatsoever.
The Act of Succession forbids the heir to the throne to be or to marry a Roman Catholic. However, marriages to Roman Catholics are reasonably common on the fringes of the Royal Family. The Duchess's son, the Earl of St Andrews, and her brother-in-law, Prince Michael of Kent, have both married Roman Catholics and formally renounced their rights of succession to the throne.
Conversion to Roman Catholicism is much rarer in the Royal Family than marriage to a Catholic. The last notable example was King Charles II, who converted on his deathbed in 1685. He had fathered at least 14 children, none legitimately. His brother James had converted in 1668, and married a Catholic as his second wife. He was driven from the country by a Protestant rebellion, headed by his son-in- law, William of Orange.
The memory of such excitements was deprecated by all parties involved yesterday. A statement from Cardinal Basil Hume said: 'The Duchess of Kent's decision to become a Roman Catholic is a purely personal one. We must all respect a person's conscience in these matters, and I know that the Duchess recognises how much she owes to the Church of England, for which she retains a genuine affection.'
The Archbishops of Canterbury and York, who have been aware of the Duchess's intentions for some time, also explained that her decision was a purely private one.
Her office denied that her conversion had anything to do with the forthcoming ordination of women priests in the Church of England, which has led one government minister, Ann Widdecombe, to become a Catholic, and seems certain to have the same effect on John Gummer, the Secretary of State for the Environment.