Traditionally Easter used to be the time when hellfire and stoppage was preached from the platforms of competing teachers' conferences. These days, regrettably, the Churches are getting in on the act. Over the weekend the fabulous Norman pile at Durham surrendered its calm to the far-from-pacific message delivered by its bishop, Tom Wright. Sermonising about the Human Fertilisation and Embryology Bill, currently before Parliament, the bishop criticised the Government for “pushing through, hard and fast, legislation that comes from a militantly atheist and secularist lobby”.

Stop the sermon right there. My NUT/religion comparison is an even better fit than I realised. The legislation emanates from a “militantly atheist and secularist lobby”? Oh yes, that would be it. Haven't you seen them on the streets and on your screens, all got up in their God Is Dead, Christians Should be Deader atheist headbands and red robes, burning Bibles, insisting on the teaching of Dawkins and Hitchens in school RS lessons, smashing icons and creeping up behind bishops and lifting their cassocks?

Sermon continues: “This secular utopianism is based on a belief in an unstoppable human ability to make a better world, while at the same time it believes that we have the right to kill unborn children and surplus old people...” Now, this is as close to a lie as makes no difference. Dr Wright may reply directly to the Times letters page, which, even in this fallen age, generally prints the words of high clergymen, to tell me which significant secularist body, or scientific group, or gaggle of atheists is it that believes “we” have the right “to kill surplus old people”? Or is he referring here to voluntary euthanasia, the idea that people may have a right to end their own lives? I challenge him.

This almost wanton disregard of fairness was being deployed for the specific purpose of attacking the proposals to allow the creation and use of hybrid embryo tissue in scientific and medical research. Or, as the Bishop put it, with what was intended to be withering irony: “Gender-bending was so last century; we now do species-bending.” Now, the eminent theologian has confused Boy George with sex-change operations (a big mistake, one gathers from the singer's memoirs), so let me note instead that it was this kind of verbal looseness that so upset Lord Winston, when he heard about the Easter sermon delivered by the leader of a rival Church union, Cardinal Keith O'Brien, the Roman Catholic Archbishop of St Andrews and Edinburgh.

The Cardinal, referring variously to the proposals as “hideous” and “grotesque”, suggested that animal-human embryos were to be created “with the excuse” that some diseases might be cured, and went on: “One might say that in our country we are about to have a public government endorsement of experiments of Frankenstein proportion.” One might say it, but it would it be - as the professor argued - untrue, though it is possible that Lord Winston had read more Mary Shelley than the Cardinal, and that he therefore knew that no one was remotely suggesting or attempting to create a new form of life, as Baron Frankenstein was.

The Cardinal would have been closer in literary, though not factual, terms had he invoked The Island of Dr Moreau, upon which H.G.Wells located the eponymous lunatic's attempt to create man-beasts. And it may be this too that inhabits the imagination of those commentators made queasy by the very idea of cellular hybrids. William Rees-Mogg, on these pages yesterday, wrote entertainingly of the element of disgust conjured up by such a prospect, and the fear of sinful mixing has always had a strong place in religious taboos. The third book of the Bible, Leviticus, is devoted to nothing else. “Whatsoever hath no fins nor scales in the waters, that shall be an abomination unto you,” said the Lord, ruling out lobster. Nor could you partake of “the stork, the heron after her kind, and the lapwing, and the bat”.

Somehow we have overcome the genuine feeling of disgust at the prospect of even touching a prawn, just as we have more recently learned to cope with homosexual acts and racially mixed marriages. These transitions can be wonderfully rapid - one notes that two thirds of the God-imparted stuff in Leviticus was rather summarily ditched in a single letter of St Paul to the Corinthians.

And I hardly need, do I, to point out that no embryo can be kept alive for more than two weeks? In any case the argument about what is actually in the Bill has been sidetracked by the mass complaints about the decision by the Government to put a three-line whip on Labour MPs. This has led, among other miracles, to the call by the Catholic hierarchy for there to be a free vote - a “conscience” vote - on the entirely contradictory basis that, according to Cardinal Cormac Murphy-O'Connor: “Catholics have got to act according to their Catholic convictions.” But these are not personal convictions, they're matters of doctrine. Churches constantly change their collective minds about what God says, so what is being asked is that MPs put their Church - not their conscience - above everything else.

Naturally, despite this, just about every editorial in every newspaper lined up, almost languidly, behind the free-vote demand. But in some cases only because they assumed that the Bill will be passed. It is an easy concession to make to the religious lobby - over reproductive rights, homosexual rights, human rights - providing that you don't believe they'll win. That way the churchy can go back to their bishops and say they've done their bit, and the rest of us can have our Bills to ameliorate or improve the human condition. Then, when the Bill becomes law and, over time, the advances save lives, the bishops and their flocks can quietly benefit from the measures they so denigrated, have the operation, swig the medicine and move on, sanctimoniously, to the next bit of opposition.

Like most of the Godless (or Godfree), I have no desire to proselytise for atheism or to persuade people out of religions that may offer them comfort and companionship. But there is a growing shrillness and unpleasantness - yes, an unscrupulousness - about the way that some of the top faithful increasingly choose to conduct their arguments. This needs to be combated because, for all their talk of conscience, what Dr Wright and Cardinal O'Brien really seem to want is to tell the rest of us how to live.

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