The position of the Roman Catholic Church in Britain has changed enormously in my lifetime, but one could never have guessed that we should see reported on the same day a recent ex-Prime Minister becoming a convert, and the Catholic weekly attendance numbers overtaking the Anglican. When I was young, no-popery prejudice still had real influence; it was not as strong in England as in Northern Ireland, nor as strong as English antiSemitism, but it could affect people’s lives in terms of marriages, school places or jobs. In politics, a Roman Catholic Prime Minister was unthinkable, and a Roman Catholic Lord Chancellor was actually illegal.

The announcement of Tony Blair’s conversion is an important personal event for Blair and his family, but it is also an important historic event. When he last saw the Pope, Blair presented him with an autographed photograph of Cardinal Newman, the most significant Catholic convert of the 19th century. Blair has himself become the most significant British convert since Newman.

Religion is not a matter of mere statistics, nor are these statistics simple. Yet the fact that Catholic weekly church attendances in England have overtaken Anglican by 862,000 to 853,000 is significant. One should nevertheless qualify it. The Catholic figures have been raised by Polish immigration. The Poles bring Polish Catholicism with them; they are a devout nation. If one counts the numbers of people who would regard themselves as Church of England, if not practising, they would still outnumber Roman Catholics, similarly self-described.

So England did not wake up yesterday morning as a Catholic country. Indeed Protestant Churches of England, Pentecostal, Methodist and Baptist, have a combined church attendance of 822,000. But the Roman Catholics should be seen as one of three large Christian groups, marginally the largest by the measure of church attendance. There are a billion Catholics in the world as a whole; that in itself adds to their influence in Britain.

There are political issues that have lain below the surface, which will now have to be reconsidered. In constitutional terms the most important concerns the monarchy. The Act of Settlement makes the English crown a Protestant monarchy. It provides that no one can be eligible to secure the crown if a Roman Catholic or married to one. This has even been made to extend to minor members of the Royal Family who have to renounce their remote rights of succession on marriage to a Roman Catholic.

Few serious politicians want to amend the Act of Settlement, not because they feel reverence for its Protestant character, which reflects quarrels of 300 years ago, but because they are afraid of opening a can of worms. Mr Blair himself may have hesitated for similar reasons before making his intended conversion public.

If the Westminster Parliament were to amend the Act of Settlement, it would be necessary for the other Commonwealth countries in which the Queen is head of state to amend their constitutions, otherwise they might end up with different monarchs. Any amendment to the Act of Settlement would open the way for Australia, and any of the other Commonwealth countries that have kept the Queen, to become republics.

Amendment would also open the way for the removal of another obvious discrimination, which is that of gender. The English crown passes in the male line, so long as there is a direct male heir. If Prince Charles had predeceased his mother, before having children, the successor to the throne would not have been the Princess Royal, though she is older than her other brothers, but Prince Andrew, followed by his daughters, followed by Prince Edward, followed by his children. There is a widespread feeling, not only among militant feminists, that this is an unjustifiable discrimination against women, and perhaps unlawful under the Human Rights Act.

Neither the discrimination against Roman Catholics nor that against women would be tolerated if the Act of Settlement had to be drafted in the present age. Both would have to go, if either of them was removed. There is a greater constitutional difficulty in the possible break-up of the United Kingdom and of Canada. Any amendment of the Act of Settlement would give Alex Salmond an opportunity to press the case for Scottish independence.

In Canada, the problem is Quebec. The reason that Canada has remained a monarchy is that Canadian governments have feared any change in the status of Canada would give an opening to the Quebec separatists. Quebec, unlike Scotland, is predominantly Catholic.

This is the tangle that has to be unwound. All the remaining monarchies of the Commonwealth might choose to become republics. Scotland may become independent; Quebec may become independent; women might rank equally with men in the succession to the English crown; Catholics might be able to succeed to the English throne. One can see why prime ministers have been so reluctant to open this constitutional question.

If one could leave these sleeping dogs to lie, personally I would do so. But I suspect the dogs are already awake. We cannot stop Australia becoming a republic, if the Australians want to. Nor can we stop Scotland becoming independent, if it chooses. We cannot go on discriminating against women and Catholics. Reforming the Act of Settlement may take as long as reforming the House of Lords, but changes will come, better early than late, better late than never.

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