THEIR bodies lie unmarked and unmourned in a forgotten corner of St Mary's cemetery in Lanark. They are the orphans of Smyllum - babies and children who died over the course of a hundred painful years and were buried beneath the grass without ceremony, without headstones, and without dignity.

Now, thanks to a year-long campaign by surviving orphans, a fitting memorial is to be erected to the estimated 150 forgotten children.

Until now, only a simple stone cross marked the mass grave of the infants who died at the home. All it said was ''Sweet Jesus have mercy on the souls of the children of Smyllum''.

They died between 1864 and 1964, the year the notorious orphanage closed. In recent months, a group of surviving orphans have alleged that the nuns who ran the home were guilty of unholy cruelty towards their charges.

They demanded that the religious order, the Sisters of Charity, pay for a fitting memorial to the ''lost children''. Campaigner Jim Kane, from Forth in Lanarkshire, yesterday confirmed that the Sisters have finally agreed to foot the bill.

''This brings to a conclusion a very unhappy chapter in the life of Smyllum orphanage,'' he said.

Now aged 62, Mr Kane was resident in the orphanage as a child. He regards the nuns' decision as finally righting a long-standing wrong.

He added: ''We had to drop our original plan to list the names of all 151 children because it was impossible to find all the names.

''So many youngsters passed away during a time of high infant mortality, we didn't want to include only some of the names that we could find.''

He said his campaign group, the In-Care Abuse Society (INCAS), was satisfied that a large impressive stone monument bearing the words of an appropriate prayer will soon stand over the graves. The original stone cross will be relocated to another part of the cemetery.

The new memorial will carry the words: ''Life so short, no world to roam, they were taken so young, they never went home. So, spare a thought for them as you pass this way - a prayer if you remember day by day. Our lives so short in need of love but found in the arms of God above. Jesus said: Suffer little children come unto me.''

The inscription will end with the words: ''Proposed by the Sisters of Charity and INCAS.''

Mr Frank Docherty, 59, from East Kilbride, another Smyllum orphan who claims to have survived two years of beating and humiliation at the home during the 1950s, said: ''This will go some way to easing the pain of surviving former Smyllum orphanage people. It's the least anyone can do for these lost children who never made it in life.''

The nuns of Smyllum, many of whom are buried in graves with proper crosses and headstones in another corner of St Mary's cemetery, interred the babies and children in paupers' graves because they did not have the financial resources to give them decent burials. They kept no records of names and details.

Years later, there are few clues to when the children died, how they died, and whether their deaths were investigated and recorded within the requirements of the law. However, there has been no suggestion that any death was other than natural.

The Smyllum home is now demolished and a housing estate stands in its place.