The Government has been urged to broaden the investigation into how unmarried mothers and their children were treated to include all the institutions from which up to 100,000 children were adopted.

A large group of Irish women, some of them mothers, others who had been child victims of the system, spoke of their horrific experiences during a hearing in the European Parliament organised by Sinn Féin.

They fear the terms of reference, due to be announced by the Government this month, will concentrate on around nine institutions identified as mother-and-baby homes.

But Dr Sean Lucey, a healthcare and welfare historian in Queens University Belfast, warned that this would not be enough to fully address the issue.

There were a range of other institutions, including the Magdalene Laundries, County Homes and mental institutions that were “Ireland’s architecture of containment” as well as the boarding-out of illegitimate children, their fostering and adoption.

“The historical evidence demonstrates that this whole network was interconnected, with women transferred between those institutions — and the inquiry should focus on the issue of unmarried motherhood and illegitimate children in general and not be a piecemeal and illogical approach,” he told the hearing.

The findings of a limited inquiry, which appeared to be what the Government favoured, would quickly be undermined as further issues were raised, he warned.

“Much ire has focused on the religious that ran those institutions. However, there are a range of other actors, including families, the medical profession, lawyers, local government and those in so-called respectable society that facilitated the running of these institutions and the political classes of the day.”

Niall Meehan, who works with those who had been in Bethany House and other Protestant institutions said there was little difference there. They were privatised institutions used by the State to abdicate responsibility, especially for vulnerable citizens. “They criminalised childbirth and ignored the male crimes of rape, incest and assault,” he added.