The Church of England has thrown down the gauntlet to the government over the issue of same-sex marriage. The message is clear: "Do as we say or there will be dire consequences."

Their response to the government consultation on its intention to legalise civil marriages between same-sex couples is overwrought to the point of hysteria. It is manipulative to the point of blackmail.

It seems the Church of England has decided to adopt the tactics that are currently being used by the Catholic Church against the Obama administration in America. There, the Church is bringing a legal action to challenge to the President's health insurance mandate on the grounds that it would involve them in the provision of contraceptives.

Although the US Government has said that the Catholic Church would not have to pay this element of the insurance for its employees working in hospitals and schools, the bishops are still undeterred. They have banded together to launch a court challenge to force the government into retreat.

And it is at this point that it becomes clear that this is not, as they claim, about "religious freedom" at all. It is about establishing how far the power of the Church can reach into secular government; how much ground it can gain in the lawmaking process.

The primary - but hidden - purpose is to humiliate the President and cause him to climb down from the main plank of his election promise - which was to introduce health insurance for all. Grandiose talk of protecting "religious freedom" conceals what is really going on. Now "religious freedom" seems to mean the right for religious bodies to do whatever they like without consequences.

If Obama capitulates, the Church will then move on to its next objective which will probably be the banning of abortion. The politicians, anxious not to receive another bloody nose from their eminences will offer little resistance..

The same thing is happening in Britain. The Church of England says that eventually the European Court of Human Rights will force it to conduct same-sex marriages in churches. And besides which - according to the consultation response - there is no difference between civil marriage and religious marriage. They are both for the same purpose - for a man and a woman to produce children.

It says the government doesn't have the right to "redefine" marriage.

But the government regularly redefines marriage, as does the church. Let us not forget that in the Old Testament it was usual for men to have several wives. Indeed, King Solomon is said to have had 700 wives.

At one time divorce was illegal, but the government changed that (again, in the teeth of furious opposition from the churches). Marriage has changed constantly over the centuries and it will weather another change - it might even be strengthened.

But the real purpose of this challenge from the Church of England is as much about staking out its territory in the political arena as it is about gay marriage. Mr Cameron is in the same position as Barack Obama - if he backs down the Church will have won a major political victory on which it will build an even more reactionary empire.

And that is bad news for all those of us who value the progress our society has made in the past few decades.

Let us not forget that the Church of England tried to exempt itself from the Human Rights Act when it was going through parliament. It tried to exempt itself from the Equality Act, saying it had a special right to discriminate where others had none. It stands in the way of the legalisation of assisted dying, even though polls show that 80%of the population would support it.

It wants more money for its buildings, its schools and the many other projects connected with the Big Society that would help it extend its influence into a society that has mainly rejected it.

The increasingly reactionary and unpleasant church has a regressive agenda that it will, if it can win this battle, happily impose on us all.