Network Rail worker was using “hopelessly inaccurate” diagram

David McDermott suffered “catastrophic injuries” in the incident resulting in significant loss of function and years of surgery.

He had been with a colleague in a mobile platform fixing an isolated section of cable when he touched a live wire and was struck by a 25,000 volt power surge.

Sheriff Alistair Watson described Mr McDermott’s injuries as “catastrophic” and said no penalty would set a price or value on the pain and suffering he continued to endure.

Network Rail was fined £130,000 after it admitted failing to provide safe working documentation and ensuring work was only done on isolated sections of line.

The sheriff added: “The obvious failure in the system, which is perhaps self-evident, is the fact that the schematic or diagram used as an essential guide for those involved in the repair operation was hopelessly inaccurate for a considerable length of time, despite it potentially being an issue of life and death importance.

“It appears to have been in continuous use by those who entrusted their safety to their employer. Put bluntly, this meant that a serious accident of this type, while perhaps not inevitable, was eventually highly foreseeable.”

Sheriff Watson also voiced his “grave concern” over the delay of seven years for the case to reach court, which prosecutors blamed on technical hitches involving statements and different agents being involved in the case.

Kilmarnock Sheriff Court heard the firm has since improved working systems.