Since 1945, Britain has become increasingly pluralist and secular. Phil Woolas, the Immigration Minister, points to the multi-faith character of British society as a reason for expecting change in the constitutional position of the Church of England. Reform of the House of Lords since new Labour took office has not extended to the 26 “Lords Spiritual” who sit on the Bishops' Bench. That debate, Mr Woolas believes, will take place.

The debate is indeed right. Even so, there remains a powerful case for antidisestablish- mentarianism. The Church of England has informed and sometimes enriched public affairs owing to its responsibility for ministering to the nation and not only to the faithful. It has done so, moreover, in the presence of competing voices in the public square for several centuries.

At least since 1662, when the settlement failed to accommodate the Puritans, there has been a significant dissenting tradition. The evangelical revival, principally through the medium of Methodism, allied to the migration of Irish Catholic labourers increased the diversity of Christian voices in the 19th century. The growth of secularism and the discoveries of modern science have confronted the Church with a serious intellectual challenge for some 200 years. The welcome development of modern Britain as a multiracial and cosmopolitan society has altered the pattern of religious observance. But this is an evolution rather than an abrupt alteration in British national life.

The Church's service to the nation has been of unarguably variable quality in modern times. Archbishop Cosmo Gordon Lang of Canterbury was among the most prominent voices in support of appeasement and the Munich agreement in the 1930s. Yet his immediate successor, William Temple, dwelt long and far more thoughtfully on public affairs. His short book Christianity and Social Order, published in 1942, shaped postwar thinking on the development of the welfare state. The testimony of Bishop George Bell of Chichester, Temple's contemporary, remains an important voice on the ethics of warfare.

Rowan Williams, the present Archbishop of Canterbury, has acquired detractors, owing partly to a tendency to rhetorical obscurity and also (as with his remarks last February on Sharia) to a willingness to advance ideas that are only half-baked. Yet his determination to prevent schism in the Church - notably on the issue of homosexuality - ought to be seen as an act of public service rather than merely as moral ambiguity. The Church exists for the nation, and believes it has an obligation to fulfil.

Disestablishment would in a sense allow the Church of England to be more Christian. Its concerns would be less expansive, and a more distinctive voice might thereby emerge. Whether that is the right course for the Church and for the nation is a conversation worth holding. It should, however, be conducted with an eye to posterity, if not eternity. While a national church might appear an anachronism, changing its status must not be undertaken lightly.

Above all, this is an issue on which the Church itself should deliberate. Politicians have transient authority, whereas the Church has existed for centuries. For a decision that would be irrevocable, there is no need to adopt a timetable.