A Liberal Democrat MP today introduced a private members Bill in the House of Commons seeking to change the rules of succession to the throne, including giving women and Catholics equal rights.
The bill had no chance of success, and was duly killed off by the government, but it has significantly moved forward the debate and the chances of lasting reform.
Both the Prime Minister, Gordon Brown and the Leader of the Opposition, David Cameron have said they favour change and wish to go ahead with consultation among members of the Commonwealth, whose agreement they regard as desirable though not essential.
Dr Evan Harris's Royal Marriages and Succession to the Crown Bill would have ended both the centuries-old ban on the monarch marrying a Catholic and the rule of primogeniture, under which a woman in the line of succession is automatically superseded by a younger male sibling.
Under Britain's archaic system of privilege and preference, the monarch is also automatically the 'supreme governor' of the Church of England in all matters - spiritual as well as temporal.
But while it is still possible that the monarch and her or his consort could be 'in communion' with the Church though married to a Jew, a Muslim or an atheist, Catholics are banned because of the 1701 Act of Settlement. They were seen as "the Taliban of their day", said the Bishop of Winchester on BBC Radio 4 today.
A BBC poll today indicated that a majority of the public (between 81 and 89 per cent) favour an end to discrimination against Catholics and women.
But the Church of England is still resisting change because it fears that the move will re-open the equally strong case for disestablishment and because it shares the government's fear that questions about a monarchical system based on hereditary privilege will also be raised. Australia has come close to seceding from the Crown in recent years.
The Justice Secretary, Jack Straw promised to ensure "soundings" were taken amongst Commonwealth countries and to report the outcome of the debate to the Prime Minister after today's debate - in which no-one directly opposed reform.
Gordon Brown, who is visiting Brazil, said "this is a very complex issue", but declared himself in favour of change in the long run.
However Dr Harris, who put forward the bill, accused Mr Straw of dealing a "serious blow" to the prospects of early reform and said Mr Brown's apparent backing for it was just "spin".
Speaking after the debate, he said: "Jack Straw was asked three times to provide either a timetable, a commitment to a Government Bill before the next election or any other tangible step towards this necessary and popular reform, but said he couldn't provide any."
"The Liberal Democrats, with cross-party backbench allies, will seek every opportunity to keep this on the agenda," Harris added.
The Bishop of Winchester has sought to portray the move as a "secularist conspiracy", but it is backed by a significant number of Christians, including those polled by the BBC.
Gordon Brown and Buckingham Palace have already discussed plans to change the rules of succession to the throne, it is being reported.
Meanwhile, Henry Bellingham, the Conservative shadow Justice Minister, suggested that the Church of England was in "no fit state" to engage in such an important debate because of its internal weaknesses.
Morale was low, church attendance was declining, its message was confused and many church buildings were falling into disrepair, he claimed.
The Church of England rejected these suggestions, but also set its face against constitutional change and sought to defend its privileged position within the state, although it attracts only two per cent of the population to its regular services.
Simon Barrow, co-director of the religion and society think-tank Ekklesia, commented: "The current arrangements for Royal succession are clearly discriminatory and unacceptable in a plural society. They should be changed. But the nub of the issue is the continuing anomaly of the establishment of the Church of England, which is acting as a brake on constitutional reform. Ending the subservience of the church to the Crown would enable it to stop fretting about its own power and status, and start attending more fully and freely to the radical call of the Christian message - which is precisely about rejecting privilege and embracing transformation."
During the past few years, the case for disestablishment has been posed on a number of occasions - most recently by senior Labour peer Lord Desai - but also by ex-bishops, theologians and members of the Free Churches.
Speaking at the recent Convention on Modern Liberty in London, URC minister Vaughan Jones said: "My [Reformed] tradition has long since sought the separation of church and state, valuing democracy in both. It believes that freedom of worship and association are fundamentals balanced by the obligation to obey the law and the right to oppose unjust laws. Faith communities have no right to ask for special privilege based on historical settlements. Constitutional reform that included disestablishment would do us all a lot of good."