THE Catholic Church in Scotland has said a “full investigation” should be made into any suspicion over the deaths of some children following the possible discovery of a mass grave used by a former orphanage.

At least 400 children are thought to have been buried in the grave at St Mary’s Cemetery in Lanark. All were residents of a care home run by Catholic nuns.

The research by the BBC’s File on 4 programme in conjunction with a Sunday newspaper focused on Smyllum Park Orphanage in Lanark.

The orphanage opened in 1864 and provided care for orphans and children from broken homes. It closed in 1981, having looked after 11,600 children.

A burial plot containing the bodies of a number of children was uncovered by two former residents of Smyllum in 2003.

Frank Docherty and Jim Kane discovered an overgrown, unmarked section of St Mary’s Cemetery during their efforts to reveal physical abuse they said many former residents had suffered. In 2004, the campaigners said the Daughters of Charity told them their records suggested children had been buried in 158 compartments in the graveyard.

The men, who both died earlier this year, believed the numbers were far higher as the nuns had indicated their records were incomplete.

The investigation indicates that at least 400 children were buried in the plot. The death records indicate that most of the children died of natural causes, from diseases common at the time such as tuberculosis, pneumonia and pleurisy.

A spokesperson for the Catholic Church said yesterday: “The death of children in care is always tragic. Any suggestion that the deaths of some children were caused by anything other than natural causes should be investigated to the fullest extent possible.

“The Catholic Church has never had any responsibility for or ability to place children in care – that has always been and remains a matter for the statutory authorities who placed children in care and were subsequently responsible for their welfare. These authorities alone can comment on the outcome of some of their placements and the standard of care expected.

“Despite this, between 2001 and 2015 the Catholic Church issued a number of apologies to anyone who had ‘suffered any form of abuse at the hands of those representing the Catholic Church’. Most recently, in August 2015, Archbishop Philip Tartaglia offered ‘a profound apology to all those who have been harmed and who have suffered in any way as a result of actions by anyone within the Catholic Church’.”

What happened at Smyllum is one of the topics being examined by the Scottish Child Abuse Inquiry.

Two representatives of the Daughters of Charity gave evidence to the inquiry this summer in which they said they could find no records of any abuse taking place. A spokesperson said they were “co-operating fully” with the inquiry and believed that was the “best and most appropriate forum for such investigations”.

They added: “As Daughters of Charity our values are totally against any form of abuse and thus, we offer our most sincere and heartfelt apology to anyone who suffered any form of abuse whilst in our care”.

A Scottish Government spokesperson said: “Clearly these are serious allegations and our thoughts are with the families of those affected.

“We recognise the great hurt and damage caused to those who were abused in childhood by the very individuals and institutions who should have cared for them. That is why we established an independent inquiry into the abuse of children in care – one of the widest-ranging public inquiries that Scotland has ever seen.”

File on 4: The Secrets of Smyllum Park will be broadcast on BBC Radio 4 tomorrow night.