A forensic soil scientist who gave evidence at the World's End trial is to help search for the remains of a schoolgirl who disappeared nearly six decades ago.

Professor Lorna Dawson of the Hutton Institute will take on the "painstaking" work of helping to find the body of Moira Anderson.

The schoolgirl was 11 when she disappeared from her home in Coatbridge, North Lanarkshire, in February 1957 while running an errand for her grandmother.

Prosecutors last year took the unusual step of announcing that convicted paedophile Alexander Gartshore, who died in 2006, would have faced prosecution for the schoolgirl's murder if he were still alive.

The Coatbridge bus driver, who was 85 when he died, was the last person to see Moira alive and had long been connected with the case.

The Crown Office today announced that Prof Dawson has been enlisted to help find Moira's remains, and stressed that the case will remain open until they are traced.

A spokesman said: "Given the public concern about the disappearance of Moira Anderson, the Lord Advocate last year took the unprecedented step of naming Alexander Gartshore as the person who would have been indicted for her murder had he been alive today.

"The Lord Advocate also instructed the investigation remain open in the hope that one day her body may be found and her family be given the closure they deserve.

"The Lord Advocate is delighted that Professor Lorna Dawson of the Hutton Institute has agreed to help in the search for Moira's remains.

"Given it is 57 years since Moira disappeared this is likely to be difficult and painstaking work. However, the case will remain open until her remains are found."

Prof Dawson, based in Aberdeen, runs a lab dedicated to forensic soil science. She has worked on more than 70 cases from around the world and helped bring World's End killer Angus Sinclair to justice last year.

She was one of a number of expert witnesses who gave evidence at his trial at the High Court in Livingston for the 1977 murders of 17-year-olds Christine Eadie and Helen Scott.