Up to 400 children died at a Scottish orphanage run by nuns and were buried in a single unmarked grave, new research has revealed.

The Daughters of Charity of St Vincent de Paul, which ran the Smyllum Park orphanage in Lanarkshire, has previously acknowledged that 158 children were buried in compartments at a nearby cemetery.

But there have long been suspicions that the real figure was far higher.

Now research carried out by BBC Radio 4's File on Four programme and the Sunday Post newspaper, including a trawl of more than 15,000 official records, has revealed hundreds of children died at Smyllum - far more than the charity that ran it has admitted.

The investigation into Smyllum Park orphanage reveals 402 babies, toddlers and children died there between 1864 and when it closed its doors in 1981.

Most of the children sent to live at the orphanage who died were buried in an unmarked mass grave at St Mary's Cemetery.