Lanark, Scotland. (Credit: David Falconer via Shutterstock)

A mass grave holds the remains of 400 children who died in an orphanage run by Catholic nuns in Scotland over the course of a century, according to a new investigation by British journalists.

The findings were a joint look into the Smyllum Park Orphanage by reporters from the BBC File on 4 program and the Sunday Post newspaper.

The revelations come amid an official ongoing Scottish Child Abuse Inquiry looking into the home, and the Daughters of Charity of St. Vincent de Paul which ran it from 1864 to 1981.

The Catholic order cared for more than 11,000 children over that time. Relatives and survivors of the orphanage claim widespread abuse from their years there—including beatings, cold baths and deprivations.

Abuse allegations led two activists named Frank Docherty and Jim Kane to launch a campaign resulting in the discovery of an unmarked section of St. Mary’s Cemetery in Lanark in 2003.

An unknown number of bodies lay in the earth there. The Daughters told the two activists the next year that children may have been buried in more than 150 plots at the cemetery.

Both activists died earlier this year. But the journalistic investigation claims now the remains of more than 400 children are there.

The journalists scrutinized thousands of death certificates over three months.

Roughly a third of the deceased were aged five or younger.

What death records have been kept indicate that most of the children died of natural causes, from tuberculosis, pneumonia and other common ailments of the time.

The Sunday Post issue was published yesterday. “The Secrets of Smyllum Park” will be broadcast on BBC Radio 4 on Tuesday.

The Scottish Child Abuse Inquiry resumes its “Phase 1” investigation of Smyllum Park and the Daughters-led Bellevue House in Rutherglen on Oct. 31.

But a “Phase 2” will commence on Nov. 28. The authorities are still seeking witnesses through a “leave to appear” notice.

The Daughters said in a statement to the journalists that they were cooperating “fully” within the inquiry.

Since its closing in 1981, the orphanage was sold off and partitioned into apartments.

The mass burials of Smyllum Park appear to resemble the untold deaths at the Bon Secours Mother and Baby Home in Tuam, County Galway, in Ireland. The probes into that site have been attempting to trace the ultimate fates of nearly 800 children