Tuesday’s vote in the House of Lords brings the prospect of same-sex marriage that much closer.  There is, no doubt, some way still to go as we enter the committee stage, with the legislation itself, the modifications required to the Matrimonial Causes Act 1973 and further changes, of varying weight, to an estimated 3,000 items of existing legislation.

Same-sex marriage did not feature in the Conservative manifesto or in any Queen’s speech.  Apparently David Cameron rejected the possibility of reform when it was raised in talks with Nick Clegg in 2009.

Arguments in favour of same-sex marriage have rarely risen above a simplistic appeal to ‘fairness’ and ‘equality’, or Cameron’s empty rhetoric that he is in favour not despite being a Conservative but because he is a Conservative and that it is ‘the right thing to do’.  Anyone who questions the wisdom of extending marriage to unions which did not formerly qualify is immediately dismissed as homophobic.  Some undoubtedly are, but others present compelling arguments.

By the Government’s own figures, only 6% of the population are homosexual; only 3% of eligible gays have taken advantage of civil partnerships and only 1% will marry if given the opportunity.  Even amongst homosexuals only 39% support making same-sex marriage a political priority.

It is also the case that civil partnerships offer all the rights and protections under the law that marriage does.  It is good legislation, relatively simple and is working well.  Legislation for same-sex marriage is superfluous.

There are many issues one might therefore reasonably expect to be far more pressing, not least galloping family breakdown, mass fatherlessness and the decline of marriage.  It was Cameron himself who promised in December 2010 to make Britain ‘the most family-friendly country in Europe’ and greater support for the ‘wonderfully precious institution’ of marriage – though he avoided any specific commitment.

In August 2011 he proclaimed,

 from here on I want a family test applied to all domestic policy.  If it hurts families, if it undermines commitment, if it tramples over the values that keep people together, or stops families from being together, then we shouldn’t do it.

As Telegraph columnist Fraser Nelson said recently, ‘Cameron’s original case for marriage was never about finger-wagging morality, but hard social logic, backed up by mountains of studies.  Marriage remains the most powerful anti-poverty tool ever invented, the best and cheapest source of health, wealth and education – and… one of the surest routes to happiness’.  Of couples who remain together until their child is 16 a staggering 97% are married – so why has Cameron suddenly abandoned his commitment?

What the Government is doing displays a contempt for the family and ‘the values that keep people together’; this is not organic evolution but radical societal revolution.  It has been a profoundly undemocratic and thus tyrannical process: when culture minister Maria Millar said there had been full public consultation she lied – the public were only consulted on how same-sex marriage should be implemented.

Cameron would seem to be playing a dangerous game then, riding rough-shod over his fellow parliamentarians and over the electorate.  One might wonder why he is so hell-bent on introducing a measure which has split the Conservatives, lost life-long voters, driven disenfranchised Tories to try their chances with UKIP but which few are bothered about.  Whatever else may be behind it, no one believes he has suddenly acquired compassion for gays.

The question inevitably arises, what is he up to?

According to Sunday Telegraph columnist Christopher Booker the answer lies with the C of E; no, not the Church of England but the Council of Europe.

The origin of the campaign to introduce same-sex marriage lies in a 2010 alliance between the Conservative Home Secretary, Theresa May, the Liberal Democrat Equalities Minister, Lynne Featherstone, and a group of gay rights lobbyists led by the organisation Equal Love, pushing the issue through the Council of Europe, rather than through Westminster.  In a pamphlet signed by May just before the 2010 General Election the Conservatives pledged themselves to consider legislative change to enable civil partnerships to be re-classified as marriages.

In June the European Court of Human Rights (ECHR) had ruled that Article 8 – the right to family life – could be applied equally to same sex relationships.  Shortly afterwards Featherstone announced new rules allowing religious music to be played at civil partnership ceremonies (but not at civil weddings), characterising it as the first step towards gay marriage.

In December Peter Tatchell and Equal Love supported a group of same-sex couples take a case to the ECHR, claiming that ‘banning’ gay marriage sent ‘a signal that we are regarded as socially and legally inferior’.

David Cameron is particularly vulnerable to any ECHR judgement which should find against the UK, having failed to honour his ‘cast iron’ 2009 pledge to repeal the Human Rights Act.  Judgement is expected close to the 2015 General Election; should it go against a UK which has no equal marriage legislation in place the ECHR could force Cameron to overturn his policy with potentially devastating political consequences.   Better to get this awkward business out of the way mid-term and head off such an outcome.

In March 2011 an official policy document, Working for Lesbian, Gay, Bisexual and Transgender Equality: Moving Forward, committed the Government to develop legislation for equal marriage.  When Britain took over chairmanship of the Council of Europe in November it pushed the issue to the top of the agenda; at a secret meeting of the Council in March 2012 – the first from which the public were excluded – detailed plans were discussed to implement legislation by June 2013; the English President of the ECHR, Sir Nicolas Bratza (who had earlier defended the blanket criminalisation of all male homosexual acts in the 1981 case of Dudgeon v the United Kingdom), pledged that if a sufficient number of countries put same-sex marriage into law by then he would promote same-sex marriage as a European human right.  Hence the unseemly rush by countries such as France and the UK to put their legislative programmes on hold and to force gay marriage into law.

The Government’s campaign has been characterised not merely by indecent haste but also by low threats and dirty tricks.  It has been an astonishingly dishonest campaign, and not merely because the true reason for the legislation has been hidden from the public.  Existing marriage legislation does not, as the Government and Peter Tatchell claim, ‘ban’ gay couples from marrying, any more than it bans a man, as one wit put it, from marrying an orange.   Instead, it defines marriage in such a way that same-sex unions – and those with oranges – are an impossibility.  Marriage is still best defined, in the formulation of Lord Penzance, as

 the voluntary union for life of one man and one woman to the exclusion of all others.

The gay marriage campaign does not lift an imaginary ban: it seeks to rewrite the definition of marriage so as to include same sex unions.  Whether or not this is, as Cameron says, the right thing to do, it is important to understand that nothing less is proposed.

This is a significant step beyond civil partnerships which, as I have said, offer the same legal rights and protections as marriage, because it redefines the very institution of marriage and thus impinges on heterosexual marriages as well as gay ones.  This is the redefinition  of an institution which has endured for millennia, despite profound social change and the depredations of recent legislation, including the 1969 Divorce Reform Act which many believed would abolish marriage altogether.

No one knows what the consequences of this measure will be.  Certainly Cameron doesn’t.  Figures from Holland show a decline in marriage overall since the introduction of same-sex marriage and a steady fall in same-sex weddings themselves after an initial enthusiasm.

The press have focussed on the more lurid consequences of the proposed legislation such as the implications for royal succession (which I won’t go into here), and the necessity to redefine adultery and consummation.  Adultery is defined as consensual sexual intercourse between a married person and someone of the opposite sex other than their spouse.  It is organ-specific and requires some degree of penetration (Dennis v Dennis [1955]).  When cited as a reason for divorce it must be proved, either by a confession or by the conception of a child.  For this reason heterosexual petitioners are often advised to use unreasonable behaviour instead.  The extra difficulty in proving homosexual adultery and the impossibility of defining it mean that adultery will be removed from law entirely.

The inescapable effect of that will be the removal of what was once the only justification of divorce and the effective condonation of extramarital affairs.

Even more difficult to define is homosexual consummation.  Heterosexual consummation is also organ-specific and must be ‘ordinary and complete and not partial and imperfect’ (D-E v A-G [1845] 163 ER 1039).  The husband must achieve a sustainable erection, there must be vaginal penetration to a significant depth and for a reasonable period of time, but there does not need to be the ‘emission of seed’ (see W v W [1967] 1 WLR 1554).

In the eyes of the law a marriage which has not been consummated is voidable and can be annulled; unlike a divorce, a marriage which is annulled never took place.  Abolishing the concept of consummation will remove the link between sex and marriage and thus the vital role marriage plays in creating the next generation.

The implications are widespread – any definition of marriage, religious or secular, will include the procreation of legitimate children, faithful companionship and lawful sexual union.  Already 50% of children are born outside of marriage; what the Government proposes is a regime in which birth within marriage is immaterial and sex outside is no longer unlawful.  Under such rules people will wonder, as they must do in Holland, what exactly is to be gained any longer by marrying.

This leads directly to the most momentous consequence of the legislation which will be the shift from marriage as a socially significant and valuable institution to marriage as a merely personal and private one, a process already well under way.  This argument enables opposition to same-sex marriage to be presented as mere bigotry and interference in a personal choice.  Marriage is reduced to consumerist choice; gender is no longer seen in law as fixed and natural but as a matter of individual choice which can be changed at will; sexual orientation, too, becomes mutable and a matter of choice.

For some Christians same-sex marriage represents a tipping point: a slide towards increasing personal, family and social dysfunction, increasing divorce, abortion on demand and an attitude that people, relationships and human life itself are all in some way ‘disposable’.  Some have called it a rebellion against God.

We can dismiss such views as homophobic bigotry or fundamentalism.  Or we can question the Government’s motives and demand to know what it thinks the consequences will be.  Some think the real agenda is the complete abolition of marriage.  They may be right.  Ultimately, it will be homosexuals who are short-changed by this reform.