Dominic Lawson: So you'd rather not think about late abortions?

Rowan Williams is, apparently, the wrong sort of doctor. The Archbishop of Canterbury is being roundly abused for his article marking the 40th anniversary of the Abortion Act, in which he agonised over the fact that almost 200,000 abortions a year now take place in this country. Doesn't Dr Williams realise that under British law it's up to "real" doctors to sign the forms if a woman wants a termination – not doctors of divinity? That, at least, seems to be the line taken by a number of the Archbishop's critics.

They seem to have been especially provoked by Dr Williams's observation that while one in four pregnancies are now aborted by medical intervention , "the pregnant woman who smokes or drinks heavily is widely regarded as guilty of infringing the rights of her unborn child".

Much though I admire Rowan Williams's courage in diving head-first into such turbulent waters, the basic premise of his article – that this was never meant to be the outcome – unwittingly misrepresents the true nature of what happened during the debate 40 years ago. The Archbishop declares that "most of those who voted for the 1967 Abortion Act did so in the clear belief that they were making provision for extreme and tragic situations: conception as a result of rape, foetal or perinatal complications, threatening a mother's life. Forty years on, many of these people have expressed their dismay at what has happened."

Well, if they are dismayed or surprised, then they clearly weren't listening at the time. Anyone who has actually read the text of the parliamentary debates in 1966 and 1967 knows that the opponents of the measure argued repeatedly that while it provided that two doctors must give their assent to an abortion for "social reasons", the effect of the legislation would be abortion on demand. This was exactly the intention of the main lobby group behind the measure, The Abortion Law Reform Association, whose motto was: "Every woman has a right to an abortion and every child has a right to be born wanted". (Not, please note, the right just to be born).

The "two doctors" provision was a classically British piece of hypocrisy, designed to allow the squeamish to square their vote with their consciences. As NHS Blog Doctor recently observed on his website: "When I was reading law, our tutor put David Steel's new Abortion Act in front of us and said, 'OK boys, this is abortion on demand.' What nonsense. We argued and argued. You have to get two doctors to certify. There has to be a risk to the mother's life etc etc. He just smiled."

Even 25 years ago David Steel complained – to his authorised biographer—that "abortion is, I am afraid, being used as a contraceptive. The present level is too high." It is now, of course, very much higher. I wonder what Sir David would regard as an appropriate or acceptable number. Actually, I don't wonder: I have more respect for those who argue openly for abortion on demand and declare that it is no business of politicians to question the conduct of women whose immediate circumstances they know nothing about.

The successor generation of MPs are now marking the anniversary of Steel's Act with a re-examination, not of the law as a whole, but of that aspect which deals with foetal viability. This clause stems from the old Infant Life (Preservation) Act of 1929, which stated that no unborn child could be killed who was "capable of being born alive." The 1967 Act stipulated that limit as 28 weeks, but in the Human Fertilisation and Embryology Act of 1990 it was brought down to 24 weeks, to reflect the advances in the treatment of very premature babies. A parliamentary committee has been deliberating whether further medical progress justifies another lowering of the "viability" threshold, to 22 or 20 weeks' gestation.

It is amazing that MPs should be deliberating at great length over this matter – which is a purely medical issue – while completely ignoring the main change which the 1990 HFEA introduced. For while it reduced the period during which "normal" foetuses could be terminated, it legalised the abortion of those for whom there was a "substantial risk of being seriously handicapped" right up to the moment of natural birth.

Yet again the British legislature was designedly vague about what this meant. At the time two professors of law, John Finnis and John Keown, wrote a one-page circular for members of parliament which warned that this could mean that foetuses of over six months' gestation with such treatable conditions as a "harelip or cleft palate" could be legally aborted. Up popped David Steel. He declared: "I deplore the circular ... a gross calumny on the medical profession ... totally discreditable." Harriet Harman said that the two professors should be reported to the Law Society or the Bar Council for even daring to publish such an opinion.

I imagine that Sir David Steel and the Deputy Leader of the Labour Party (as Ms Harman now is) will have read last weekend's newspaper reports of statistics from the South West Congenital Anomaly Register showing that a number of babies – sorry, foetuses – with cleft lips and palates have recently been aborted at between 27 and 34 weeks. A consultant in foetal medicine defended this practice, arguing that "cleft palate and cleft lip can be associated with underlying genetic syndromes that we cannot diagnose in the womb." Best not to take any risks, eh, chaps?

It is much more comfortable not to think about these things. A very late termination is a profoundly traumatic experience for the mother – but there's more to it than that, much more. Last week a Dispatches documentary, Abortion: What We Need to Know, showed footage of the human detritus left behind after such abortions. I have very mixed feelings about the broadcasting of these images. If we regard such tiny but fully-formed humans as worthy of some respect – as I do– is it right for them to become posthumous performers in a snuff movie? The Guardian's television critic argued that even to show such images was inappropriate in a programme which purported to be "fair and accurate reporting".

I am not so sure about that. If you were making a documentary about lynching in the Deep South would you refuse high-mindedly to reproduce the disgusting visible evidence of what actually happened? If you were making a film about the Nazis' concentration camps, would you refrain from showing those horrible images of mounds of emaciated corpses? I am not saying that doctors who perform late-term abortions are like the Ku Klux Klan or the Gestapo – but we cannot dismiss from discussion the images from the Dispatches documentary, however much we might want to. Perhaps we should describe them as the inconvenient truth.

d.lawson@independent.co.uk