How can it be inappropriate for a Bible teacher to speak about the heterosexual nature of true marriage when the Church of England's official teaching is so clear and explicit? Canon A5 clearly states that the Book of Common Prayer, together with the 39 Articles and the Ordinal, faithfully expresses the biblical doctrine of the Church of England. The BCP in its marriage service leaves no room for doubt that heterosexual marriage is the only right context for the expression of sexual love and that it is the God-given context for the upbringing of children.

In stating "the causes for which Matrimony was ordained", the BCP teaches the congregations witnessing the marriage of one man to one woman:

"First, it was ordained for the procreation of children, to be brought up in the fear and nurture of the Lord, and to the praise of his holy Name. Secondly, it was ordained for a remedy against sin, and to avoid fornication; that such persons as have not the gift of continency might marry, and keep themselves undefiled members of Christ's body. Thirdly, it was ordained for the mutual society, help, and comfort, that the one ought to have of the other, both in prosperity and adversity."

Surely any Anglican minister when questioned on the nature of marriage should articulate the biblical teaching as expressed in the Anglican tradition. Surely to refuse to do so is as serious a dereliction of ministerial duty as, for example, refusing to conduct divine service at the appointed time. Very arguably, given the importance of the God-created institution of heterosexual marriage in the Bible, it is a more serious abdication of responsibility than that.

Surely also Christmas is an especially important time for all Anglican ministers to re-iterate the importance of heterosexual marriage for the common good and particularly for the well-being of children. For the Incarnate Son of God, our Lord Jesus Christ, was born, albeit by supernatural conception, into a faithful, loving, monogamous, heterosexual marriage.

Archbishop Welby is a fine Christian example as a devoted husband and father in his personal life. Unfortunately on this occasion, in ducking out of an opportunity to contend for biblical truth on the BBC, he did not set us as frontline parochial clergy a good ministerial example to follow.

Julian Mann is vicar of the Parish Church of the Ascension, Oughtibridge, South Yorkshire, UK - www.oughtibridgechurch.org.uk . He blogs as Cranmer's Curate - www.cranmercurate.blogspot.co.uk