The discovery of a grave containing the remains of as many as 800 babies at a former home for unmarried mothers in Ireland is yet another problem for the Irish Catholic Church.

The mother and baby home at Tuam in County Galway was run by the nuns of the Sisters of Bon Secours and operated between 1925 and 1961. It took in thousands of women who had committed the “mortal sin” of unwed pregnancy, delivered their babies and was charged with caring for them.

But unsanitary conditions, poor food and a lack of medical care led to shockingly high rates of infant mortality. Babies' bodies were deposited in a former sewage tank.

Sadly, the mass grave at Tuam is probably not unique. I visited the site — the home was demolished in the 1970s — and spoke with locals who remember babies' skulls emerging from the soil around their houses. When boys broke open the cover of the sewage pit, they found it “full to the brim” of skeletons.

Tuam was only one of a dozen mother and baby homes in Ireland in the years after World War II, all of which treated their inmates in a similar fashion.

During 10 years of research into the Catholic Church's treatment of “fallen women” — I wrote about one of them in my book, “Philomena,” later turned into a feature film starring Dame Judi Dench — I discovered that the girls were refused medical attention, including painkillers, during even the most difficult births; the nuns told them the pain was the penance they must pay for their sin.

In the home where Philomena gave birth, an unkempt plot bears the names of babies and mothers, some as young as 15. There are undoubtedly many more there who have no memorial.

With hindsight, the church argues that it was performing a socially necessary task, helping to solve the problem of “illegitimate” children.

It is true that pregnant girls would have been shunned by their families and left with no one to turn to. But the fact is that the church itself had created the problem by the stigma it attached to unmarried sex — and by its refusal to allow contraception or sex education in any form.

It is too late to bring back the dead babies of Tuam or to undo the damage done to thousands of innocent mothers and children. But there are ways that a modicum of justice could still be done.

The Irish government has offered financial compensation to former inmates of the Magdalene laundries, where women were confined for reasons ranging from prostitution and sexual indiscretion to disobedience and mental deficiency. But my impression, though, is that the victims want more than money.

A full and unreserved apology would help.

Martin Sixsmith's book, “Philomena,” published by Penguin Books, was adapted for the screen last year.