An 83-year-old man has pleaded guilty to amassing what is believed to be the largest collection of child sexual abuse material ever seized by Police Scotland. Alan MacPherson amassed more than two million images over more than a decade, with 805,306 identified as depicting child sexual abuse, many classified as Category A, the most severe.
Falkirk Sheriff Court heard that the sheer volume of material discovered at MacPherson's home in Stenhousemuir, Stirlingshire, overwhelmed police capacity for categorization. Officers seized nine devices, with vile images found on all of them. A full examination of five devices revealed nearly 1.4 million images that remained ungraded.
Prosecutor Rachel Wallace stated that in July of the previous year, numerous Category A images of child sexual exploitation were uploaded via the messaging app Session during an online chat with an undercover police officer. The IP address used was traced to MacPherson's residence, leading to a police raid.
Wallace explained that due to the overwhelming quantity, a limited grading strategy was implemented. On a single solid-state drive, officers graded 698,924 child sexual abuse files but had to leave an additional 1.374 million files ungraded. The victims were primarily girls aged nine to 15, with at least one possibly as young as seven, being abused by men or posing sexually.
MacPherson was arrested and, during an interview, admitted to searching online for indecent images of children for years for his own personal gratification. He is a first-time offender.
His solicitor-advocate, Stephen Biggam, noted that MacPherson is deaf, suffers from macular degeneration, and has withdrawn from community involvement since his arrest.
Sheriff Craig Harris ordered MacPherson to be remanded into custody, citing the nature, scale, and duration of the offenses, as well as the risk he poses when at liberty. The sheriff also placed MacPherson on the sex offenders register and called for background reports before a sentencing hearing next month.