Amnesty International, the human rights charity, has long enjoyed widespread support from religious groups. Its 2.2 million members include thousands of practising Roman Catholics and evangelical Christians, many of whom have been drawn by its staunch opposition to the death penalty and torture in all circumstances. In recent weeks, however, scores of religious members have been resigning. On Tuesday, Cardinal Keith O’Brien, the head of the Catholic Church in Scotland, became the latest prominent figure to gave up his membership.

Their cause is the charity’s new position on abortion. Throughout its 46-year history, Amnesty has always avoided taking a stance on termination of pregnancy, mindful that its members include both secular liberals who regard it as a human right and religious conservatives who see it as murder. That changed in April, when it backed the decriminalisation of abortion and pronounced it a right in some circumstances.

Amnesty’s antiabortion members have accused the charity of betrayal, saying the policy undermines efforts to uphold the sanctity of all life.

Many have noted that its founder, Peter Benenson, was a Catholic convert who would likely have disapproved, and the Vatican has called for a moratorium on donations. Rock for Life, an antiabortion group, has even accused the charity of duping the pop stars Christina Aguilera and Avril Lavigne, both Christians who oppose abortion, into promoting it by performing on a record to raise money for survivors of the genocide in Darfur.

To judge from these attacks, and the coverage they have received, you might imagine that Amnesty had become the political wing of abortion providers such as Marie Stopes and the British Pregnancy Advisory Service. The Daily Mail, for example, has run headlines such as: “Catholic bishop quits Amnesty as it backs abortion”.

Yet look in detail at what the charity has said, and it is clear that this is gross distortion.

Amnesty could in no sense be described as “pro-abortion”, as its critics would have it. It could not even fairly be described as “pro-choice”.

The new policy takes no view at all on the rights and wrongs of abortion. It is doing nothing to promote it, and it is not even arguing that women should always be allowed to choose. All it has done is to state its opposition to blanket legal prohibitions on the procedure, and to lay out circumstances in which it can be the only compassionate option: in cases of rape and incest, and when the mother’s life or health is in danger.

Even many opponents of abortion agree that it is often acceptable, if regrettable, in such conditions. It is certainly appropriate for a charity that campaigns against torture to call for abortion to be available when rape is used as a weapon of terror. That its agenda is humanitarian is also made clear by its strong opposition to forced or coerced abortion, which it describes as another form of torture. This is no extreme campaign.

It is hard, too, to think of a more fundamental human right than the liberty to seek a medical procedure that might save one’s life. In situations such as ectopic pregnancy, most women who do not have an abortion will die, particularly in developing countries, where medical care does not meet Western standards. Access to a sanitary abortion in these circumstances is a matter of health. Amnesty should not be dissuaded from speaking out by theology.

Catholics and evangelicals are, of course, within their rights to decide which organisations to join and to support financially. They should ask themselves, however, whether they really think support for human rights means denying abortions to rape victims and women with ectopic pregnancies. Amnesty, too, should proudly resist their pressure. Its attitude, not theirs, is the one that is most compatible with its mission of respect for life.

Mark Henderson is the Science Editor The Times

Times recommends

• Live chat: Thrifty ways to update your winter wardrobe
• Is anybody out there really listening?
• Nutrition Q&A: Will eating late make me fat?