News that the Church of Scotland and Church of England have made a formal agreement to become ecumenical partners and to work jointly together on a variety of initiatives in future is little short of a religious revolution, the sort Calvin and Knox would have recognised as seismic. As befits our times, however, this historic step, outlined in a document called the Columba Declaration, has been taken not with great fanfare, but with quiet determination. The result of decades of deliberation and consultation, it has been distinguished by the thoughtfulness and lack of stridency for which the ecumenical movement is renowned.

Moves have been afoot to ratify this long-standing association since the 1960s, but we cannot be accused of being cynical for suggesting that the growing secular mood of the country has given added impetus to this union. In light of declining church membership, of whatever denomination, the matters that separate the Church of Scotland and the Church of England are negligible compared to the overlap in beliefs and practices. It is interesting too that this amalgamation comes in the wake of the independence referendum. As the report accompanying the declaration notes, “what unites us as churches immeasurably transcends the boundaries of our two particular nations”.

Former Kirk Moderator, the Very Rev Sheilagh Kesting, who was co-secretary of the group that prepared the report, is one of the most influential figures in the movement. Blessed with the reserves of patience and diplomacy required for those hoping to bring change to such barnacled, slow-moving establishments, she has remained steadfast in the heated atmosphere of Kirk assemblies and committees, where minor differences of doctrinal interpretation have sparked splenetic argument and lifelong enmities. If there are ample grounds for combustion within a single church, how much more inflammatory might it be when two great institutions contemplate combining forces?

Yet as she and her fellow ecumenists have been wise to recognise from a very early stage, drawing together churches from different but not dissimilar traditions, is a long-term process, the ecclesiastical equivalent of reducing carbon emissions or healing old political rifts. It could even be argued that the multiplicity of theological positions that the Kirk tolerates and contains, has proved helpful in enabling the Columba Declaration. Whatever differences those in one church discover in the other can be viewed merely as a reflection of their own diversity.

And what a sensible step they have taken. Such collaboration, such willingness to seek areas of agreement rather than of schism – which the Kirk in particular has been overly prone to do – is an inspirational example of fusion, of forgetting the past and pooling resources in order to get across a shared message. By joining hands, as it were, they will be able to bolster the cause of Christianity in a society where, if its voice is not exactly drowned out, is too often seen as backward-looking or insular or irrelevant. In a week when hundreds of thousands will flock to churches to mark Christmas and the good news it brings, this small but significant event also deserves to be celebrated.